Blood coagulation protein conjugates

ABSTRACT

The invention relates to materials and methods of conjugating a water soluble polymer to an oxidized carbohydrate moiety of a blood coagulation protein comprising contacting the oxidized carbohydrate moiety with an activated water soluble polymer under conditions that allow conjugation. More specifically, the present invention relates to the aforementioned materials and methods wherein the water soluble polymer contains an active aminooxy group and wherein an oxime linkage is formed between the oxidized carbohydrate moiety and the active aminooxy group on the water soluble polymer. In one embodiment of the invention the conjugation is carried out in the presence of the nucleophilic catalyst aniline. In addition the generated oxime linkage can be stabilized by reduction with NaCNBH 3  to form an alkoxyamine linkage.

This application is a Continuation of U.S. application Ser. No.14/988,931 filed Jan. 6, 2016 (now abandoned), which is a Continuationof U.S. application Ser. No. 14/136,266 filed Dec. 20, 2013 (nowabandoned), which is a Continuation of U.S. application Ser. No.12/843,542 filed Jul. 26, 2010 (now issued as U.S. Pat. No. 8,637,640),which claims benefit of U.S. Provisional Application Ser. No. 61/347,136filed May 21, 2010, and U.S. Provisional Application Ser. No. 61/228,828filed Jul. 27, 2009, all of which are incorporated herein by referencein their entirety.

FIELD OF THE INVENTION

The present invention relates to materials and methods for conjugating awater soluble polymer to a blood coagulation protein.

REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM,LISTING APPENDIX SUBMITTED ON A COMPACT DISK

This invention incorporated by reference the Sequence Listing text copysubmitted herewith, which was created on Nov. 30, 2017, entitled008073_137_US03_ST25.txt which is 8 kilobytes in size.

BACKGROUND OF THE INVENTION

Therapeutic polypeptides such as blood coagulation proteins includingFactor IX (FIX), Factor VIII (FVIII), Factor VIIa (FVIIa), VonWillebrand Factor (VWF), Factor FV (FV), Factor X (FX), Factor XI (FXI),Factor XII (FXII), thrombin (FII), protein C, protein S, tPA, PAI-1,tissue factor (TF) and ADAMTS 13 protease are rapidly degraded byproteolytic enzymes and neutralized by antibodies. This reduces theirhalf-life and circulation time, thereby limiting their therapeuticeffectiveness. Relatively high doses and frequent administration arenecessary to reach and sustain the desired therapeutic or prophylacticeffect of these coagulation proteins. As a consequence, adequate doseregulation is difficult to obtain and the need of frequent intravenousadministrations imposes restrictions on the patient's way of living.

PEGylation of polypeptide drugs protects them in circulation andimproves their pharmacodynamic and pharmacokinetic profiles (Harris andChess, Nat Rev Drug Discov. 2003; 2:214-21). The PEGylation processattaches repeating units of ethylene glycol (polyethylene glycol (PEG))to a polypeptide drug. PEG molecules have a large hydrodynamic volume(5-10 times the size of globular proteins), are highly water soluble andhydrated, non-toxic, non-immunogenic and rapidly cleared from the body.PEGylation of molecules can lead to increased resistance of drugs toenzymatic degradation, increased half-life in vivo, reduced dosingfrequency, decreased immunogenicity, increased physical and thermalstability, increased solubility, increased liquid stability, and reducedaggregation. The first PEGylated drugs were approved by the FDA in theearly 1990s. Since then, the FDA has approved several PEGylated drugsfor oral, injectable, and topical administration.

Polysialic acid (PSA), also referred to as colominic acid (CA), is anaturally occurring polysaccharide. It is a homopolymer ofN-acetylneuraminic acid with α(2→8) ketosidic linkage and containsvicinal diol groups at its non-reducing end. It is negatively chargedand a natural constituent of the human body. It can easily be producedfrom bacteria in large quantities and with pre-determined physicalcharacteristics (U.S. Pat. No. 5,846,951). Because thebacterially-produced PSA is chemically and immunologically identical toPSA produced in the human body, bacterial PSA is non-immunogenic, evenwhen coupled to proteins. Unlike some polymers, PSA acid isbiodegradable. Covalent coupling of colominic acid to catalase andasparaginase has been shown to increase enzyme stability in the presenceof proteolytic enzymes or blood plasma. Comparative studies in vivo withpolysialylated and unmodified asparaginase revealed that polysialylationincreased the half-life of the enzyme (Fernandes and Gregoriadis,Biochimica Biophysica Acta 1341:26-34, 1997).

The preparation of conjugates by forming a covalent linkage between thewater soluble polymer and the therapeutic protein can be carried out bya variety of chemical methods. For example, coupling of PEG-derivativesto peptides or proteins is reviewed by Roberts et al. (Adv Drug DelivRev 2002; 54:459-76). One approach for coupling water soluble polymersto therapeutic proteins is the conjugation of the polymers via thecarbohydrate moieties of the protein. Vicinal hydroxyl (OH) groups ofcarbohydrates in proteins can be easily oxidized with sodium periodate(NaIO4) to form active aldehyde groups (Rothfus et Smith, J Biol Chem1963; 238:1402-10; van Lenten et Ashwell, J Biol Chem 1971;246:1889-94). Subsequently the polymer can be coupled to the aldehydegroups of the carbohydrate by use of reagents containing, for example,an active hydrazide group (Wilchek M and Bayer E A, Methods Enzymol1987; 138:429-42). A more recent technology is the use of reagentscontaining aminooxy groups which react with aldehydes to form oximelinkages (WO 96/40662, WO2008/025856).

Additional examples describing conjugation of a water soluble polymer toa therapeutic protein are described in WO 06/071801 which teaches theoxidation of carbohydrate moieties in Von Willebrand factor andsubsequent coupling to PEG using hydrazide chemistry; US Publication No.2009/0076237 which teaches the oxidation of rFVIII and subsequentcoupling to PEG and other water soluble polymers (e.g. PSA, HES,dextran) using hydrazide chemistry; WO 2008/025856 which teachesoxidation of different coagulation factors, e.g. rFIX, FVIII and FVIIaand subsequent coupling to e.g., PEG, using aminooxy chemistry byforming an oxime linkage; and U.S. Pat. No. 5,621,039 which teaches theoxidation of FIX and subsequent coupling to PEG using hydrazidechemistry.

Recently, an improved method was described comprising mild periodateoxidation of sialic acids to generate aldehydes followed by reactionwith an aminooxy group containing reagent in the presence of catalyticamounts of aniline (Dirksen A et Dawson P E, Bioconjugate Chem. 2008;19, 2543-8; and Zeng Y et al., Nature Methods 2009; 6:207-9). Theaniline catalysis dramatically accelerates the oxime ligation, allowingthe use of very low concentrations of the reagent.

Notwithstanding the methods available of conjugating water solublepolymers to therapeutic proteins, there remains a need to developmaterials and methods for conjugating water soluble polymers to proteinsthat improves the protein's pharmacodynamic and/or pharmacokineticproperties while minimizing the costs associated with the variousreagents.

SUMMARY OF THE INVENTION

The present invention provides materials and methods for conjugatingpolymers to proteins that improves the protein's pharmacodynamic and/orpharmacokinetic properties while minimizing the costs associated withthe various reagents.

In one embodiment of the invention, a method of conjugating a watersoluble polymer to an oxidized carbohydrate moiety of a bloodcoagulation protein comprising contacting the oxidized carbohydratemoiety with an activated water soluble polymer under conditions thatallow conjugation; the blood coagulation protein selected from the groupconsisting of Factor IX (FIX), Factor VIII (FVIII), Factor VIIa (FVIIa),Von Willebrand Factor (VWF), Factor FV (FV), Factor X (FX), Factor XI(FXI), Factor XII (FXII), thrombin (FII), protein C, protein S, tPA,PAI-1, tissue factor (TF) and ADAMTS 13 protease or a biologicallyactive fragment, derivative or variant thereof; the water solublepolymer containing an active aminooxy group and is selected from thegroup consisting of polyethylene glycol (PEG), branched PEG, polysialicacid (PSA), carbohydrate, polysaccharides, pullulane, chitosan,hyaluronic acid, chondroitin sulfate, dermatan sulfate, starch, dextran,carboxymethyl-dextran, polyalkylene oxide (PAO), polyalkylene glycol(PAG), polypropylene glycol (PPG), polyoxazoline,polyacryloylmorpholine, polyvinyl alcohol (PVA), polycarboxylate,polyvinylpyrrolidone, polyphosphazene, polyoxazoline,polyethylene-co-maleic acid anhydride, polystyrene-co-maleic acidanhydride, poly(1-hydroxymethylethylene hydroxymethylformal) (PHF),2-methacryloyloxy-2′-ethyltrimethylammoniumphosphate (MPC); and thecarbohydrate moiety oxidized by incubation with a buffer comprising anoxidizing agent selected from the group consisting of sodium periodate(NaIO4), lead tetraacetate (Pb(OAc)4) and potassium perruthenate(KRuO4); wherein an oxime linkage is formed between the oxidizedcarbohydrate moiety and the active aminooxy group on the water solublepolymer.

In another embodiment of the invention, the water soluble polymeraccording to the aforementioned method is PSA. In a related embodiment,the PSA is comprised of about 5-500 or 10-300 sialic acid units. Instill another embodiment, the blood coagulation protein according to theaforementioned method is FIX. In another embodiment, the bloodcoagulation protein according to the aforementioned method is FVIIa. Instill another embodiment, the blood coagulation protein according to theaforementioned method is FVIII. In yet another embodiment, theaforementioned method is provided wherein the oxidizing agent is sodiumperiodate (NaIO4). In another embodiment, the oxidized carbohydratemoiety of the blood coagulation protein according to the aforementionedmethod is located in the activation peptide of the blood coagulationprotein.

In yet another embodiment of the invention, the aforementioned method isprovided wherein the PSA is prepared by reacting an activated aminooxylinker with oxidized PSA;

-   -   wherein the aminooxy linker is selected from the group        consisting of:    -   a 3-oxa-pentane-1,5-dioxyamine linker of the formula:

and

-   -   a 3,6,9-trioxa-undecane-1,11-dioxyamine linker of the formula:

wherein the PSA is oxidized by incubation with a oxidizing agent to forma terminal aldehyde group at the non-reducing end of the PSA. In stillanother embodiment, the aforementioned method is provided wherein theactivated aminooxy linker comprises 1-50 ethylene glycol units.

In still another embodiment, an aforementioned method is providedwherein the aminooxy linker is 3-oxa-pentane-1,5-dioxyamine. In arelated embodiment, the oxidizing agent is NaIO₄.

In another embodiment of the invention, the aforementioned method isprovided wherein the contacting of the oxidized carbohydrate moiety withthe activated water soluble polymer occurs in a buffer comprising anucleophilic catalyst selected from the group consisting of aniline andaniline derivatives.

In yet another embodiment of the invention, an aforementioned method isprovided further comprising the step of reducing an oxime linkage in theconjugated blood coagulation protein by incubating the conjugated bloodcoagulation protein in a buffer comprising a reducing compound selectedfrom the group consisting of sodium cyanoborohydride (NaCNBH3) andascorbic acid (vitamin C). In a related embodiment the reducing compoundis sodium cyanoborohydride (NaCNBH3).

In another embodiment of the invention, a modified blood coagulationprotein produced by an aforementioned method is provided.

In still another embodiment of the invention, a modified FIX is providedcomprising a FIX molecule or a biologically active fragment, derivativeor variant thereof; and at least one aminooxy PSA bound to the FIXmolecule, wherein said aminooxy PSA is attached to the FIX via one ormore carbohydrate moieties.

In another embodiment of the invention, a modified FVIIa is providedcomprising a FVIIa molecule or a biologically active fragment,derivative or variant thereof; and at least one aminooxy PSA bound tothe FVIIa molecule, wherein said aminooxy PSA is attached to the FVIIavia one or more carbohydrate moieties.

In still another embodiment of the invention, a modified FVIII isprovided comprising a FVIII molecule or a biologically active fragment,derivative or variant thereof; and at least one aminooxy PSA bound tothe FVIII molecule, wherein said aminooxy PSA is attached to the FVIIIvia one or more carbohydrate moieties.

In still another embodiment of the invention, a modified FIX is providedcomprising a FIX molecule or a biologically active fragment, derivativeor variant thereof; and at least one aminooxy PEG bound to the FIXmolecule, wherein said aminooxy PEG is attached to the FIX via one ormore carbohydrate moieties.

In another embodiment of the invention, a modified FVIIa is providedcomprising a FVIIa molecule or a biologically active fragment,derivative or variant thereof; and at least one aminooxy PEG bound tothe FVIIa molecule, wherein said aminooxy PEG is attached to the FVIIavia one or more carbohydrate moieties.

In still another embodiment of the invention, a modified FVIII isprovided comprising a FVIII molecule or a biologically active fragment,derivative or variant thereof; and at least one aminooxy PEG bound tothe FVIII molecule, wherein said aminooxy PEG is attached to the FVIIIvia one or more carbohydrate moieties.

In yet another embodiment, a water soluble polymer is providedcomprising an active aminooxy linker; said water soluble polymerselected from the group consisting of polyethylene glycol (PEG),branched PEG, polysialic acid (PSA), carbohydrate, polysaccharides,pullulane, chitosan, hyaluronic acid, chondroitin sulfate, dermatansulfate, starch, dextran, carboxymethyl-dextran, polyalkylene oxide(PAO), polyalkylene glycol (PAG), polypropylene glycol (PPG),polyoxazoline, poly acryloylmorpholine, polyvinyl alcohol (PVA),polycarboxylate, polyvinylpyrrolidone, polyphosphazene, polyoxazoline,polyethylene-co-maleic acid anhydride, polystyrene-co-maleic acidanhydride, poly(1-hydroxymethylethylene hydroxymethylformal) (PHF),2-methacryloyloxy-2′-ethyltrimethylammoniumphosphate (MPC); said activeaminooxy linker is selected from the group consisting of: a3-oxa-pentane-1,5-dioxyamine linker of the formula:

and

-   -   a 3,6,9-trioxa-undecane-1,11-dioxyamine linker of the formula:

In still another embodiment, the aforementioned method is providedwherein activated aminooxy linker comprises 1-50 ethylene glycol units.

FIGURES

FIG. 1 shows the primary structure of coagulation Factor IX.

FIG. 2 shows the coupling of oxidized rFIX to aminooxy-PSA.

FIG. 3 shows the synthesis of the water soluble di-aminoxy linkers3-oxa-pentane-1,5-dioxyamine and 3,6,9-trioxa-undecane-1,11-dioxyamine.

FIG. 4 shows the preparation of aminooxy-PSA.

FIG. 5 shows the analytical characterization of the PSA-rFIX conjugateemploying SDS-PAGE and Coomassie staining.

FIG. 6 shows the analytical characterization of the PSA-rFIX conjugateemploying detection with anti-FIX and anti-PSA antibodies.

FIG. 7 shows activity of native rFIX and PSA-rFIX conjugate relative totime post infusions.

FIG. 8 shows PSA-rFVIII and Advate levels relative to time postinfusion.

DETAILED DESCRIPTION OF THE INVENTION

The pharmacological and immunological properties of therapeutic proteinscan be improved by chemical modification and conjugation with polymericcompounds such as polyethylene glycol (PEG), branched PEG, polysialicacid (PSA), carbohydrate, polysaccharides, pullulane, chitosan,hyaluronic acid, chondroitin sulfate, dermatan sulfate, starch, dextran,carboxymethyl-dextran, polyalkylene oxide (PAO), polyalkylene glycol(PAG), polypropylene glycol (PPG), polyoxazoline,polyacryloylmorpholine, polyvinyl alcohol (PVA), polycarboxylate,polyvinylpyrrolidone, polyphosphazene, polyoxazoline,polyethylene-co-maleic acid anhydride, polystyrene-co-maleic acidanhydride, poly(1-hydroxymethylethylene hydroxymethylformal) (PHF),2-methacryloyloxy-2′-ethyltrimethylammoniumphosphate (MPC). Theproperties of the resulting conjugates generally strongly depend on thestructure and the size of the polymer. Thus, polymers with a defined andnarrow size distribution are usually preferred in the art. Syntheticpolymers like PEG can be manufactured easily with a narrow sizedistribution, while PSA can be purified in such a manner that results ina final PSA preparation with a narrow size distribution. In additionPEGylation reagents with defined polymer chains and narrow sizedistribution are on the market and commercially available for areasonable price.

The addition of a soluble polymer, such as through polysialylation isone approach to improve the properties of a blood coagulation proteinsuch as FIX, as well as other coagulation proteins (e.g., VWF, FVIIa(see, e.g., US 2008/0221032A1, incorporated herein by reference) andFVIII).

Blood Coagulation Proteins

As described herein, blood coagulation proteins including, but notlimited to, Factor IX (FIX), Factor VIII (FVIII), Factor VIIa (FVIIa),Von Willebrand Factor (VWF), Factor FV (FV), Factor X (FX), Factor XI,Factor XII (FXII), thrombin (FII), protein C, protein S, tPA, PAI-1,tissue factor (TF) and ADAMTS 13 protease are contemplated by theinvention. As used herein, the term “blood coagulation protein” refersto any Factor IX (FIX), Factor VIII (FVIII), Factor VIIa (FVIIa), VonWillebrand Factor (VWF), Factor FV (FV), Factor X (FX), Factor XII(FXII), thrombin (FII), protein C, protein S, tPA, PAI-1, tissue factor(TF) and ADAMTS 13 protease which exhibits biological activity that isassociated with that particular native blood coagulation protein.

The blood coagulation cascade is divided into three distinct segments:the intrinsic, extrinsic, and common pathways (Schenone et al., CurrOpin Hematol. 2004; 11:272-7). The cascade involves a series of serineprotease enzymes (zymogens) and protein cofactors. When required, aninactive zymogen precursor is converted into the active form, whichconsequently converts the next enzyme in the cascade.

The intrinsic pathway requires the clotting factors VIII, IX, X, XI, andXII. Initiation of the intrinsic pathway occurs when prekallikrein,high-molecular-weight kininogen, factor XI (FXI) and factor XII (FXII)are exposed to a negatively charged surface. Also required are calciumions and phospholipids secreted from platelets.

The extrinsic pathway is initiated when the vascular lumen of bloodvessels is damaged. The membrane glycoprotein tissue factor is exposedand then binds to circulating factor VII (FVII) and to small preexistingamounts of its activated form FVIIa. This binding facilitates fullconversion of FVII to FVIIa and subsequently, in the presence of calciumand phospholipids, the conversion of factor IX (FIX) to factor IXa(FIXa) and factor X (FX) to factor Xa (FXa). The association of FVIIawith tissue factor enhances the proteolytic activity by bringing thebinding sites of FVII for the substrate (FIX and FX) into closerproximity and by inducing a conformational change, which enhances theenzymatic activity of FVIIa.

The activation of FX is the common point of the two pathways. Along withphospholipid and calcium, factors Va (FVa) and Xa convert prothrombin tothrombin (prothrombinase complex), which then cleaves fibrinogen to formfibrin monomers. The monomers polymerize to form fibrin strands. FactorXIIIa (FXIIIa) covalently bonds these strands to one another to form arigid mesh.

Conversion of FVII to FVIIa is also catalyzed by a number of proteases,including thrombin, FIXa, FXa, factor XIa (FXIa), and factor XIIa(FXIIa). For inhibition of the early phase of the cascade, tissue factorpathway inhibitor targets FVIIa/tissue factor/FXa product complex.

A. Polypeptides

In one aspect, the starting material of the present invention is a bloodcoagulation protein, which can be derived from human plasma, or producedby recombinant engineering techniques, as described in U.S. Pat. Nos.4,757,006; 5,733,873; 5,198,349; 5,250,421; 5,919,766; and EP 306 968.As described herein, the term blood coagulation protein refers to anyblood coagulation protein molecule which exhibits biological activitythat is associated with the native blood coagulation protein. In oneembodiment of the invention, the blood coagulation protein molecule is afull-length blood coagulation protein.

Blood coagulation protein molecules contemplated include full-lengthproteins, precursors of full length proteins, biologically activesubunits or fragments of full length proteins, as well as biologicallyactive derivatives and variants of any of these forms of bloodcoagulation proteins. Thus, blood coagulation protein include those that(1) have an amino acid sequence that has greater than about 60%, about65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 91%,about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about98% or about 99% or greater amino acid sequence identity, over a regionof at least about 25, about 50, about 100, about 200, about 300, about400, or more amino acids, to a polypeptide encoded by a referencednucleic acid or an amino acid sequence described herein; and/or (2)specifically bind to antibodies, e.g., polyclonal or monoclonalantibodies, generated against an immunogen comprising a referenced aminoacid sequence as described herein, an immunogenic fragment thereof,and/or a conservatively modified variant thereof.

According to the present invention, the term “recombinant bloodcoagulation protein” includes any blood coagulation protein obtained viarecombinant DNA technology. In certain embodiments, the term encompassesproteins as described herein.

As used herein, “endogenous blood coagulation protein” includes a bloodcoagulation protein which originates from the mammal intended to receivetreatment. The term also includes blood coagulation protein transcribedfrom a transgene or any other foreign DNA present in said mammal. Asused herein, “exogenous blood coagulation protein” includes a bloodcoagulation protein which does not originate from the mammal intended toreceive treatment.

As used herein, “plasma-derived blood coagulation protein” or“plasmatic” includes all forms of the protein found in blood obtainedfrom a mammal having the property participating in the coagulationpathway.

As used herein “biologically active derivative” or “biologically activevariant” includes any derivative or variant of a molecule havingsubstantially the same functional and/or biological properties of saidmolecule, such as binding properties, and/or the same structural basis,such as a peptidic backbone or a basic polymeric unit.

An “analog,” “variant” or “derivative” is a compound substantiallysimilar in structure and having the same biological activity, albeit incertain instances to a differing degree, to a naturally-occurringmolecule. For example, a polypeptide variant refers to a polypeptidesharing substantially similar structure and having the same biologicalactivity as a reference polypeptide. Variants or analogs differ in thecomposition of their amino acid sequences compared to thenaturally-occurring polypeptide from which the analog is derived, basedon one or more mutations involving (i) deletion of one or more aminoacid residues at one or more termini of the polypeptide and/or one ormore internal regions of the naturally-occurring polypeptide sequence(e.g., fragments), (ii) insertion or addition of one or more amino acidsat one or more termini (typically an “addition” or “fusion”) of thepolypeptide and/or one or more internal regions (typically an“insertion”) of the naturally-occurring polypeptide sequence or (iii)substitution of one or more amino acids for other amino acids in thenaturally-occurring polypeptide sequence. By way of example, a“derivative” refers to a polypeptide sharing the same or substantiallysimilar structure as a reference polypeptide that has been modified,e.g., chemically.

Variant or analog polypeptides include insertion variants, wherein oneor more amino acid residues are added to a blood coagulation proteinamino acid sequence of the invention. Insertions may be located ateither or both termini of the protein, and/or may be positioned withininternal regions of the blood coagulation protein amino acid sequence.Insertion variants, with additional residues at either or both termini,include for example, fusion proteins and proteins including amino acidtags or other amino acid labels. In one aspect, the blood coagulationprotein molecule optionally contains an N-terminal Met, especially whenthe molecule is expressed recombinantly in a bacterial cell such as E.coli.

In deletion variants, one or more amino acid residues in a bloodcoagulation protein polypeptide as described herein are removed.Deletions can be effected at one or both termini of the bloodcoagulation protein polypeptide, and/or with removal of one or moreresidues within the blood coagulation protein amino acid sequence.Deletion variants, therefore, include fragments of a blood coagulationprotein polypeptide sequence.

In substitution variants, one or more amino acid residues of a bloodcoagulation protein polypeptide are removed and replaced withalternative residues. In one aspect, the substitutions are conservativein nature and conservative substitutions of this type are well known inthe art. Alternatively, the invention embraces substitutions that arealso non-conservative. Exemplary conservative substitutions aredescribed in Lehninger, [Biochemistry, 2nd Edition; Worth Publishers,Inc., New York (1975), pp. 71-77] and are set out immediately below.

SIDE CHAIN CHARACTERISTIC AMINO ACID Non-polar (hydrophobic): A.Aliphatic A L I V P B. Aromatic F W C. Sulfur-containing M D. BorderlineG Uncharged-polar: A. Hydroxyl S T Y B. Amides N Q C. Sulfhydryl C D.Borderline G Positively charged (basic) K R H Negatively charged(acidic) D E

Alternatively, exemplary conservative substitutions are set outimmediately below.

Conservative Substitutions II

EXEMPLARY ORIGINAL RESIDUE SUBSTITUTION Ala (A) Val, Leu, Ile Arg (R)Lys, Gln, Asn Asn (N) Gln, His, Lys, Arg Asp (D) Glu Cys (C) Ser Gln (Q)Asn Glu (E) Asp His (H) Asn, Gln, Lys, Arg Ile (I) Leu, Val, Met, Ala,Phe, Leu (L) Ile, Val, Met, Ala, Phe Lys (K) Arg, Gln, Asn Met (M) Leu,Phe, Ile Phe (F) Leu, Val, Ile, Ala Pro (P) Gly Ser (S) Thr Thr (T) SerTrp (W) Tyr Tyr (Y) Trp, Phe, Thr, Ser Val (V) Ile, Leu, Met, Phe, Ala

B. Polynucleotides

Nucleic acids encoding a blood coagulation protein of the inventioninclude, for example and without limitation, genes, pre-mRNAs, mRNAs,cDNAs, polymorphic variants, alleles, synthetic and naturally-occurringmutants.

Polynucleotides encoding a blood coagulation protein of the inventionalso include, without limitation, those that (1) specifically hybridizeunder stringent hybridization conditions to a nucleic acid encoding areferenced amino acid sequence as described herein, and conservativelymodified variants thereof; (2) have a nucleic acid sequence that hasgreater than about 95%, about 96%, about 97%, about 98%, about 99%, orhigher nucleotide sequence identity, over a region of at least about 25,about 50, about 100, about 150, about 200, about 250, about 500, about1000, or more nucleotides (up to the full length sequence of 1218nucleotides of the mature protein), to a reference nucleic acid sequenceas described herein. Exemplary “stringent hybridization” conditionsinclude hybridization at 42° C. in 50% formamide, 5×SSC, 20 mM Na.PO4,pH 6.8; and washing in 1×SSC at 55° C. for 30 minutes. It is understoodthat variation in these exemplary conditions can be made based on thelength and GC nucleotide content of the sequences to be hybridized.Formulas standard in the art are appropriate for determining appropriatehybridization conditions. See Sambrook et al., Molecular Cloning: ALaboratory Manual (Second ed., Cold Spring Harbor Laboratory Press,1989) §§ 9.47-9.51.

A “naturally-occurring” polynucleotide or polypeptide sequence istypically from a mammal including, but not limited to, primate, e.g.,human; rodent, e.g., rat, mouse, hamster; cow, pig, horse, sheep, or anymammal. The nucleic acids and proteins of the invention can berecombinant molecules (e.g., heterologous and encoding the wild typesequence or a variant thereof, or non-naturally occurring).

In certain embodiments of the invention, the aforementioned polypeptidesand polynucleotides are exemplified by the following blood coagulationproteins.

Factor VIIa

FVII (also known as stable factor or proconvertin) is a vitaminK-dependent serine protease glycoprotein with a pivotal role inhemostasis and coagulation (Eigenbrot, Curr Protein Pept Sci. 2002;3:287-99).

FVII is synthesized in the liver and secreted as a single-chainglycoprotein of 48 kD. FVII shares with all vitamin K-dependent serineprotease glycoproteins a similar protein domain structure consisting ofan amino-terminal gamma-carboxyglutamic acid (Gla) domain with 9-12residues responsible for the interaction of the protein with lipidmembranes, a carboxy-terminal serine protease domain (catalytic domain),and two epidermal growth factor-like domains containing a calcium ionbinding site that mediates interaction with tissue factor.Gamma-glutamyl carboxylase catalyzes carboxylation of Gla residues inthe amino-terminal portion of the molecule. The carboxylase is dependenton a reduced form of vitamin K for its action, which is oxidized to theepoxide form. Vitamin K epoxide reductase is required to convert theepoxide form of vitamin K back to the reduced form.

The major proportion of FVII circulates in plasma in zymogen form, andactivation of this form results in cleavage of the peptide bond betweenarginine 152 and isoleucine 153. The resulting activated FVIIa consistsof a NH₂-derived light chain (20 kD) and a COOH terminal-derived heavychain (30 kD) linked via a single disulfide bond (Cys 135 to Cys 262).The light chain contains the membrane-binding Gla domain, while theheavy chain contains the catalytic domain.

The plasma concentration of FVII determined by genetic and environmentalfactors is about 0.5 mg/mL (Pinotti et al., Blood. 2000; 95:3423-8).Different FVII genotypes can result in several-fold differences in meanFVII levels. Plasma FVII levels are elevated during pregnancy in healthyfemales and also increase with age and are higher in females and inpersons with hypertriglyceridemia. FVII has the shortest half-life ofall procoagulant factors (3-6 h). The mean plasma concentration of FVIIais 3.6 ng/mL in healthy individuals and the circulating half-life ofFVIIa is relatively long (2.5 h) compared with other coagulationfactors.

Hereditary FVII deficiency is a rare autosomal recessive bleedingdisorder with a prevalence estimated to be 1 case per 500,000 persons inthe general population (Acharya et al., J Thromb Haemost. 2004;2248-56). Acquired FVII deficiency from inhibitors is also very rare.Cases have also been reported with the deficiency occurring inassociation with drugs such as cephalosporins, penicillins, and oralanticoagulants. Furthermore, acquired FVII deficiency has been reportedto occur spontaneously or with other conditions, such as myeloma,sepsis, aplastic anemia, with interleukin-2 and antithymocyte globulintherapy.

Reference polynucleotide and polypeptide sequences include, e.g.,GenBank Accession Nos. J02933 for the genomic sequence, M13232 for thecDNA (Hagen et al. PNAS 1986; 83: 2412-6), and P08709 for thepolypeptide sequence (references incorporated herein in theirentireties). A variety of polymorphisms of FVII have been described, forexample see Sabater-Lleal et al. (Hum Genet. 2006; 118:741-51)(reference incorporated herein in its entirety).

Factor IX

FIX is a vitamin K-dependent plasma protein that participates in theintrinsic pathway of blood coagulation by converting FX to its activeform in the presence of calcium ions, phospholipids and FVIIIa. Thepredominant catalytic capability of FIX is as a serine protease withspecificity for a particular arginine-isoleucine bond within FX.Activation of FIX occurs by FXIa which causes excision of the activationpeptide from FIX to produce an activated FIX molecule comprising twochains held by one or more disulphide bonds. Defects in FIX are thecause of recessive X-linked hemophilia B.

Hemophilia A and B are inherited diseases characterized by deficienciesin FVIII and FIX polypeptides, respectively. The underlying cause of thedeficiencies is frequently the result of mutations in FVIII and FIXgenes, both of which are located on the X chromosome. Traditionaltherapy for hemophilias often involves intravenous administration ofpooled plasma or semi-purified coagulation proteins from normalindividuals. These preparations can be contaminated by pathogenic agentsor viruses, such as infectious prions, HIV, parvovirus, hepatitis A, andhepatitis C. Hence, there is an urgent need for therapeutic agents thatdo not require the use of human serum.

The level of the decrease in FIX activity is directly proportional tothe severity of hemophilia B. The current treatment of hemophilia Bconsists of the replacement of the missing protein by plasma-derived orrecombinant FIX (so-called FIX substitution or replacement treatment ortherapy).

Polynucleotide and polypeptide sequences of FIX can be found for examplein the UniProtKB/Swiss-Prot Accession No. P00740, U.S. Pat. No.6,531,298 and in FIG. 1.

Factor VIII

Coagulation factor VIII (FVIII) circulates in plasma at a very lowconcentration and is bound non-covalently to Von Willebrand factor(VWF). During hemostasis, FVIII is separated from VWF and acts as acofactor for activated factor IX (FIXa)-mediated FX activation byenhancing the rate of activation in the presence of calcium andphospholipids or cellular membranes.

FVIII is synthesized as a single-chain precursor of approximately270-330 kD with the domain structure A1-A2-B-A3-C1-C2. When purifiedfrom plasma (e.g., “plasma-derived” or “plasmatic”), FVIII is composedof a heavy chain (A1-A2-B) and a light chain (A3-C1-C2). The molecularmass of the light chain is 80 kD whereas, due to proteolysis within theB domain, the heavy chain is in the range of 90-220 kD.

FVIII is also synthesized as a recombinant protein for therapeutic usein bleeding disorders. Various in vitro assays have been devised todetermine the potential efficacy of recombinant FVIII (rFVIII) as atherapeutic medicine. These assays mimic the in vivo effects ofendogenous FVIII. In vitro thrombin treatment of FVIII results in arapid increase and subsequent decrease in its procoagulant activity, asmeasured by in vitro assays. This activation and inactivation coincideswith specific limited proteolysis both in the heavy and the lightchains, which alter the availability of different binding epitopes inFVIII, e.g. allowing FVIII to dissociate from VWF and bind to aphospholipid surface or altering the binding ability to certainmonoclonal antibodies.

The lack or dysfunction of FVIII is associated with the most frequentbleeding disorder, hemophilia A. The treatment of choice for themanagement of hemophilia A is replacement therapy with plasma derived orrFVIII concentrates. Patients with severe haemophilia A with FVIIIlevels below 1%, are generally on prophylactic therapy with the aim ofkeeping FVIII above 1% between doses. Taking into account the averagehalf-lives of the various FVIII products in the circulation, this resultcan usually be achieved by giving FVIII two to three times a week.

Reference polynucleotide and polypeptide sequences include, e.g.,UniProtKB/Swiss-Prot P00451 (FA8_HUMAN); Gitschier J et al.,Characterization of the human Factor VIII gene, Nature, 312(5992):326-30 (1984); Vehar G H et al., Structure of human Factor VIII, Nature,312(5992):337-42 (1984); Thompson A R. Structure and Function of theFactor VIII gene and protein, Semin Thromb Hemost, 2003:29; 11-29(2002).

Von Willebrand Factor

Von Willebrand factor (VWF) is a glycoprotein circulating in plasma as aseries of multimers ranging in size from about 500 to 20,000 kD.Multimeric forms of VWF are composed of 250 kD polypeptide subunitslinked together by disulfide bonds. VWF mediates initial plateletadhesion to the sub-endothelium of the damaged vessel wall. Only thelarger multimers exhibit hemostatic activity. It is assumed thatendothelial cells secrete large polymeric forms of VWF and those formsof VWF which have a low molecular weight (low molecular weight VWF)arise from proteolytic cleavage. The multimers having large molecularmasses are stored in the Weibel-Pallade bodies of endothelial cells andliberated upon stimulation.

VWF is synthesized by endothelial cells and megakaryocytes as prepro-VWFthat consists to a large extent of repeated domains. Upon cleavage ofthe signal peptide, pro-VWF dimerizes through disulfide linkages at itsC-terminal region. The dimers serve as protomers for multimerization,which is governed by disulfide linkages between the free end termini.The assembly to multimers is followed by the proteolytic removal of thepropeptide sequence (Leyte et al., Biochem. J. 274 (1991), 257-261).

The primary translation product predicted from the cloned cDNA of VWF isa 2813-residue precursor polypeptide (prepro-VWF). The prepro-VWFconsists of a 22 amino acid signal peptide and a 741 amino acidpropeptide, with the mature VWF comprising 2050 amino acids (Ruggeri Z.A., and Ware, J., FASEB J., 308-316 (1993).

Defects in VWF are causal to Von Willebrand disease (VWD), which ischaracterized by a more or less pronounced bleeding phenotype. VWD type3 is the most severe form in which VWF is completely missing, and VWDtype 1 relates to a quantitative loss of VWF and its phenotype can bevery mild. VWD type 2 relates to qualitative defects of VWF and can beas severe as VWD type 3. VWD type 2 has many sub forms, some beingassociated with the loss or the decrease of high molecular weightmultimers. Von Willebrand disease type 2a (VWD-2A) is characterized by aloss of both intermediate and large multimers. VWD-2B is characterizedby a loss of highest-molecular-weight multimers. Other diseases anddisorders related to VWF are known in the art.

The polynucleotide and amino acid sequences of prepro-VWF are availableat GenBank Accession Nos. NM_000552 and NP_000543, respectively.

Other blood coagulation proteins according to the present invention aredescribed in the art, e.g. Mann K G, Thromb Haemost, 1999; 82:165-74.

C. Production of Blood Coagulation Proteins

Production of a blood coagulation protein includes any method known inthe art for (i) the production of recombinant DNA by geneticengineering, (ii) introducing recombinant DNA into prokaryotic oreukaryotic cells by, for example and without limitation, transfection,electroporation or microinjection, (iii) cultivating said transformedcells, (iv) expressing blood coagulation protein, e.g. constitutively orupon induction, and (v) isolating said blood coagulation protein, e.g.from the culture medium or by harvesting the transformed cells, in orderto obtain purified blood coagulation protein.

In other aspects, the blood coagulation protein is produced byexpression in a suitable prokaryotic or eukaryotic host systemcharacterized by producing a pharmacologically acceptable bloodcoagulation protein molecule. Examples of eukaryotic cells are mammaliancells, such as CHO, COS, HEK 293, BHK, SK-Hep, and HepG2.

A wide variety of vectors are used for the preparation of the bloodcoagulation protein and are selected from eukaryotic and prokaryoticexpression vectors. Examples of vectors for prokaryotic expressioninclude plasmids such as, and without limitation, pRSET, pET, and pBAD,wherein the promoters used in prokaryotic expression vectors include oneor more of, and without limitation, lac, trc, trp, recA, or araBAD.Examples of vectors for eukaryotic expression include: (i) forexpression in yeast, vectors such as, and without limitation, pAO, pPIC,pYES, or pMET, using promoters such as, and without limitation, AOX1,GAP, GAL1, or AUG1; (ii) for expression in insect cells, vectors such asand without limitation, pMT, pAc5, pIB, pMIB, or pBAC, using promoterssuch as and without limitation PH, p10, MT, Ac5, OpIE2, gp64, or polh,and (iii) for expression in mammalian cells, vectors such as and withoutlimitation pSVL, pCMV, pRc/RSV, pcDNA3, or pBPV, and vectors derivedfrom, in one aspect, viral systems such as and without limitationvaccinia virus, adeno-associated viruses, herpes viruses, orretroviruses, using promoters such as and without limitation CMV, SV40,EF-1, UbC, RSV, ADV, BPV, and β-actin.

D. Administration

In one embodiment a conjugated blood coagulation protein of the presentinvention may be administered by injection, such as intravenous,intramuscular, or intraperitoneal injection.

To administer compositions comprising a conjugated blood coagulationprotein of the present invention to human or test animals, in oneaspect, the compositions comprise one or more pharmaceuticallyacceptable carriers. The terms “pharmaceutically” or “pharmacologicallyacceptable” refer to molecular entities and compositions that arestable, inhibit protein degradation such as aggregation and cleavageproducts, and in addition do not produce allergic, or other adversereactions when administered using routes well-known in the art, asdescribed below. “Pharmaceutically acceptable carriers” include any andall clinically useful solvents, dispersion media, coatings,antibacterial and antifungal agents, isotonic and absorption delayingagents and the like, including those agents disclosed above.

As used herein, “effective amount” includes a dose suitable for treatinga mammal having a bleeding disorder as described herein.

The compositions may be administered orally, topically, transdermally,parenterally, by inhalation spray, vaginally, rectally, or byintracranial injection. The term parenteral as used herein includessubcutaneous injections, intravenous, intramuscular, intracisternalinjection, or infusion techniques. Administration by intravenous,intradermal, intramuscular, intramammary, intraperitoneal, intrathecal,retrobulbar, intrapulmonary injection and or surgical implantation at aparticular site is contemplated as well. Generally, compositions areessentially free of pyrogens, as well as other impurities that could beharmful to the recipient.

Single or multiple administrations of the compositions can be carriedout with the dose levels and pattern being selected by the treatingphysician. For the prevention or treatment of disease, the appropriatedosage will depend on the type of disease to be treated, as describedabove, the severity and course of the disease, whether drug isadministered for preventive or therapeutic purposes, previous therapy,the patient's clinical history and response to the drug, and thediscretion of the attending physician.

The present invention also relates to a pharmaceutical compositioncomprising an effective amount of a conjugated blood coagulation proteinas defined herein. The pharmaceutical composition may further comprise apharmaceutically acceptable carrier, diluent, salt, buffer, orexcipient. The pharmaceutical composition can be used for treating theabove-defined bleeding disorders. The pharmaceutical composition of theinvention may be a solution or a lyophilized product. Solutions of thepharmaceutical composition may be subjected to any suitablelyophilization process.

As an additional aspect, the invention includes kits which comprise acomposition of the invention packaged in a manner which facilitates itsuse for administration to subjects. In one embodiment, such a kitincludes a compound or composition described herein (e.g., a compositioncomprising a conjugated blood coagulation protein), packaged in acontainer such as a sealed bottle or vessel, with a label affixed to thecontainer or included in the package that describes use of the compoundor composition in practicing the method. In one embodiment, the kitcontains a first container having a composition comprising a conjugatedblood coagulation protein and a second container having aphysiologically acceptable reconstitution solution for the compositionin the first container. In one aspect, the compound or composition ispackaged in a unit dosage form. The kit may further include a devicesuitable for administering the composition according to a specific routeof administration. Preferably, the kit contains a label that describesuse of the therapeutic protein or peptide composition.

Water Soluble Polymers

In one aspect, a blood coagulation protein derivative (i.e., aconjugated blood coagulation protein) molecule provided is bound to awater-soluble polymer including, but not limited to, polyethylene glycol(PEG), branched PEG, polysialic acid (PSA), carbohydrate,polysaccharides, pullulane, chitosan, hyaluronic acid, chondroitinsulfate, dermatan sulfate, starch, dextran, carboxymethyl-dextran,polyalkylene oxide (PAO), polyalkylene glycol (PAG), polypropyleneglycol (PPG) polyoxazoline, poly acryloylmorpholine, polyvinyl alcohol(PVA), polycarboxylate, polyvinylpyrrolidone, polyphosphazene,polyoxazoline, polyethylene-co-maleic acid anhydride,polystyrene-co-maleic acid anhydride, poly(1-hydroxymethylethylenehydroxymethylformal) (PHF),2-methacryloyloxy-2′-ethyltrimethylammoniumphosphate (MPC). In oneembodiment of the invention, the water soluble polymer is consisting ofsialic acid molecule having a molecular weight range of 350 to 120,000,500 to 100,000, 1000 to 80,000, 1500 to 60,000, 2,000 to 45,000 Da,3,000 to 35,000 Da, and 5,000 to 25,000 Da. The coupling of the watersoluble polymer can be carried out by direct coupling to the protein orvia linker molecules. One example of a chemical linker is MBPH(4-[4-N-Maleimidophenyl]butyric acid hydrazide) containing acarbohydrate-selective hydrazide and a sulfhydryl-reactive maleimidegroup (Chamow et al., J Biol Chem 1992; 267:15916-22). Other exemplaryand preferred linkers are described below.

In one embodiment, the derivative retains the full functional activityof native therapeutic blood coagulation protein products, and providesan extended half-life in vivo, as compared to native therapeutic bloodcoagulation protein products. In another embodiment, the derivativeretains at least 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 34,35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52,53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70,71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88,89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 110, 120, 130, 140, or150 percent (%) biological activity relative to native blood coagulationprotein. In a related aspect, the biological activities of thederivative and native blood coagulation protein are determined by theratios of chromogenic activity to blood coagulation factor antigen value(blood coagulation factor:Chr:blood coagulation factor:Ag). In stillanother embodiment of the invention, the half-life of the construct isdecreased or increased 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4,1.5, 2, 3, 4, 5, 6, 7, 8, 9, or 10-fold relative to the in vivohalf-life of native blood coagulation protein.

A. Sialic Acid and PSA

As used herein, “sialic acid moieties” includes sialic acid monomers orpolymers (“polysaccharides”) which are soluble in an aqueous solution orsuspension and have little or no negative impact, such as side effects,to mammals upon administration of the PSA-blood coagulation proteinconjugate in a pharmaceutically effective amount. The polymers arecharacterized, in one aspect, as having 1, 2, 3, 4, 5, 10, 20, 30, 40,50, 60, 70, 80, 90, 100, 200, 300, 400, or 500 sialic acid units. Incertain aspects, different sialic acid units are combined in a chain.

In one embodiment of the invention, the sialic acid portion of thepolysaccharide compound is highly hydrophilic, and in another embodimentthe entire compound is highly hydrophilic. Hydrophilicity is conferredprimarily by the pendant carboxyl groups of the sialic acid units, aswell as the hydroxyl groups. The saccharide unit may contain otherfunctional groups, such as, amine, hydroxyl or sulphate groups, orcombinations thereof. These groups may be present on naturally-occurringsaccharide compounds, or introduced into derivative polysaccharidecompounds.

The naturally occurring polymer PSA is available as a polydispersepreparation showing a broad size distribution (e.g. Sigma C-5762) andhigh polydispersity (PD). Because the polysaccharides are usuallyproduced in bacteria carrying the inherent risk of copurifyingendotoxins, the purification of long sialic acid polymer chains mayraise the probability of increased endotoxin content. Short PSAmolecules with 1-4 sialic acid units can also be synthetically prepared(Kang S H et al., Chem Commun. 2000; 227-8; Ress D K and Linhardt R J,Current Organic Synthesis. 2004; 1:31-46), thus minimizing the risk ofhigh endotoxin levels. However PSA preparations with a narrow sizedistribution and low polydispersity, which are also endotoxin-free, cannow be manufactured. Polysaccharide compounds of particular use for theinvention are, in one aspect, those produced by bacteria. Some of thesenaturally-occurring polysaccharides are known as glycolipids. In oneembodiment, the polysaccharide compounds are substantially free ofterminal galactose units.

B. Polyethylene Glycol (PEG) and Pegylation

In certain aspects, blood coagulation factor, e.g., FVIII, FVIIa, FIX,or other blood coagulation factor molecules are conjugated to a watersoluble polymer by any of a variety of chemical methods (Roberts J M etal., Advan Drug Delivery Rev 2002; 54:459-76). For example, in oneembodiment FVIII, FVIIa, or FIX is modified by the conjugation of PEG tofree amino groups of the protein using N-hydroxysuccinimide (NHS)esters. In another embodiment the water soluble polymer, for examplePEG, is coupled to free SH groups using maleimide chemistry or thecoupling of PEG hydrazides or PEG amines to carbohydrate moieties of theFVIII, FVIIa, or FIX after prior oxidation.

The conjugation is in one aspect performed by direct coupling (orcoupling via linker systems) of the water soluble polymer to bloodcoagulation factor, e.g., FVIII, FVIIa, or FIX, under formation ofstable bonds. In addition degradable, releasable or hydrolysable linkersystems are used in certain aspects the present invention (Tsubery etal. J Biol Chem 2004; 279:38118-24/Greenwald et al., J Med Chem 1999;42:3657-67/Zhao et al., Bioconj Chem 2006;17:341-51/WO2006/138572A2/U.S. Pat. No. 7,259,224B2/U.S. Pat. No.7,060,259B2).

In one embodiment of the invention, a blood coagulation factor, e.g.,FVIII, FVIIa, or FIX, is modified via lysine residues by use ofpolyethylene glycol derivatives containing an activeN-hydroxysuccinimide ester (NHS) such as succinimidyl succinate,succinimidyl glutarate or succinimidyl propionate. These derivativesreact with the lysine residues of FVIII, FVIIa, or FIX under mildconditions by forming a stable amide bond. In one embodiment of theinvention, the chain length of the PEG derivative is 5,000 Da. Other PEGderivatives with chain lengths of 500 to 2,000 Da, 2,000 to 5,000 Da,greater than 5,000 up to 10,000 Da or greater than 10,000 up to 20,000Da, or greater than 20,000 up to 150,000 Da are used in variousembodiments, including linear and branched structures.

Alternative methods for the PEGylation of amino groups are, withoutlimitation, the chemical conjugation with PEG carbonates by formingurethane bonds, or the reaction with aldehydes or ketones by reductiveamination forming secondary amide bonds.

In one embodiment of the present invention a blood coagulation factor,e.g., FVIII, FVIIa, FIX, or other blood coagulation factor, molecule ischemically modified using PEG derivatives that are commerciallyavailable. These PEG derivatives in alternative aspects have a linear orbranched structures. Examples of PEG-derivatives containing NHS groupsare listed below.

The following PEG derivatives are non-limiting examples of thosecommercially available from Nektar Therapeutics (Huntsville, Ala.; seewww.nektar.com/PEG reagent catalog; Nektar Advanced PEGylation, pricelist 2005-2006):

-   -   mPEG-Succinimidyl propionate (mPEG-SPA)

-   -   mPEG-Succinimidyl α-methylbutanoate (mPEG-SMB)

-   -   mPEG-CM-HBA-NHS (CM=carboxymethyl; HBA=Hydroxy butyric acid)

-   -   Structure of a Branched PEG-derivative (Nektar Therapeutics):    -   Branched PEG N-Hydroxysuccinimide (mPEG2-NHS)

This reagent with branched structure is described in more detail byKozlowski et al. (BioDrugs 2001; 5:419-29).

Other non-limiting examples of PEG derivatives are commerciallyavailable from NOF Corporation (Tokyo, Japan; see website:nof.co.jp/3nglish: Catalogue 2005)

General Structure of Linear PEG-Derivatives (NOF Corp.)

Structures of Branched PEG-derivatives (NOF Corp.):2,3-Bis(methylpolyoxyethylene-oxy)-1-(1,5-dioxo-5-succinimidyloxy,pentyloxy)propane

2,3-Bis(methylpolyoxyethylene-oxy)-1-(succinimidylcarboxypentyloxy)propane

These propane derivatives show a glycerol backbone with a 1,2substitution pattern. In the present invention branched PEG derivativesbased on glycerol structures with 1,3 substitution or other branchedstructures described in US2003/0143596A1 are also contemplated.

PEG derivatives with degradable (for example, hydrolysable linkers) asdescribed by Tsubery et al. (J Biol Chem 2004; 279:38118-24) andShechter et al. (WO04089280A3) are also contemplated.

Surprisingly, the PEGylated FVIII, FVIIa, FIX, or other bloodcoagulation factor of this invention exhibits functional activity,combined with an extended half-life in vivo. In addition the PEGylatedrFVIII, FVIIa, FIX, or other blood coagulation factor seems to be moreresistant against thrombin inactivation.

C. Methods of Attachment

A blood coagulation protein may be covalently linked to thepolysaccharide compounds by any of various techniques known to those ofskill in the art. In various aspects of the invention, sialic acidmoieties are bound to a blood coagulation protein, e.g., FIX, FVIII,FVIIa or VWF, for example by the method described in U.S. Pat. No.4,356,170, which is herein incorporated by reference.

Other techniques for coupling PSA to polypeptides are also known andcontemplated by the invention. For example, US Publication No.2007/0282096 describes conjugating an amine or hydrazide derivative of,e.g., PSA, to proteins. In addition, US Publication No. 2007/0191597describes PSA derivatives containing an aldehyde group for reaction withsubstrates (e.g., proteins) at the reducing end. These references areincorporated by reference in their entireties.

Various methods are disclosed at column 7, line 15, through column 8,line 5 of U.S. Pat. No. 5,846,951 (incorporated by reference in itsentirety). Exemplary techniques include linkage through a peptide bondbetween a carboxyl group on one of either the blood coagulation proteinor polysaccharide and an amine group of the blood coagulation protein orpolysaccharide, or an ester linkage between a carboxyl group of theblood coagulation protein or polysaccharide and a hydroxyl group of theblood coagulation protein or polysaccharide. Another linkage by whichthe blood coagulation protein is covalently bonded to the polysaccharidecompound is via a Schiff base, between a free amino group on the bloodcoagulation protein being reacted with an aldehyde group formed at thenon-reducing end of the polysaccharide by periodate oxidation (JenningsH J and Lugowski C, J Immunol. 1981; 127:1011-8; Fernandes A I andGregoriadis G, Biochim Biophys Acta. 1997; 1341; 26-34). The generatedSchiff base is in one aspect stabilized by specific reduction withNaCNBH3 to form a secondary amine. An alternative approach is thegeneration of terminal free amino groups in the PSA by reductiveamination with NH4Cl after prior oxidation. Bifunctional reagents can beused for linking two amino or two hydroxyl groups. For example, PSAcontaining an amino group is coupled to amino groups of the protein withreagents like BS3 (Bis(sulfosuccinimidyl)suberate/Pierce, Rockford,Ill.). In addition heterobifunctional cross linking reagents likeSulfo-EMCS (N-ε-Maleimidocaproyloxy) sulfosuccinimide ester/Pierce) isused for instance to link amine and thiol groups.

In another approach, a PSA hydrazide is prepared and coupled to thecarbohydrate moiety of the protein after prior oxidation and generationof aldehyde functions.

As described above, a free amine group of the therapeutic protein reactswith the 1-carboxyl group of the sialic acid residue to form a peptidylbond or an ester linkage is formed between the 1-carboxylic acid groupand a hydroxyl or other suitable active group on a blood coagulationprotein. Alternatively, a carboxyl group forms a peptide linkage withdeacetylated 5-amino group, or an aldehyde group of a molecule of ablood coagulation protein forms a Schiff base with the N-deacetylated5-amino group of a sialic acid residue.

Alternatively, the polysaccharide compound is associated in anon-covalent manner with a blood coagulation protein. For example, thepolysaccharide compound and the pharmaceutically active compound are inone aspect linked via hydrophobic interactions. Other non-covalentassociations include electrostatic interactions, with oppositely chargedions attracting each other.

In various embodiments, the blood coagulation protein is linked to orassociated with the polysaccharide compound in stoichiometric amounts(e.g., 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:7, 1:8, 1:9, or 1:10, etc.).In various embodiments, 1-6, 7-12 or 13-20 polysaccharides are linked tothe blood coagulation protein. In still other embodiments, 1, 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or morepolysaccharides are linked to the blood coagulation protein.

In various embodiments, the blood coagulation protein is modified tointroduce glycosylation sites (i.e., sites other than the nativeglycosylation sites). Such modification may be accomplished usingstandard molecular biological techniques known in the art. Moreover, theblood coagulation protein, prior to conjugation to a water solublepolymer via one or more carbohydrate moieties, may be glycosylated invivo or in vitro. These glycosylated sites can serve as targets forconjugation of the proteins with water soluble polymers (US PatentApplication No. 20090028822, US Patent Application No. 2009/0093399, USPatent Application No. 2009/0081188, US Patent Application No.2007/0254836, US Patent Application No. 2006/0111279, and DeFrees S. etal., Glycobiology, 2006, 16, 9, 833-43).

D. Aminooxy Linkage

In one embodiment of the invention, the reaction of hydroxylamine orhydroxylamine derivatives with aldehydes (e.g., on a carbohydrate moietyfollowing oxidation by sodium periodate) to form an oxime group isapplied to the preparation of conjugates of blood coagulation protein.For example, a glycoprotein (e.g., a blood coagulation protein accordingto the present invention) is first oxidized with a oxidizing agent suchas sodium periodate (NaIO₄) (Rothfus J A et Smith E L., J Biol Chem1963, 238, 1402-10; and Van Lenten L and Ashwell G., J Biol Chem 1971,246, 1889-94). The periodate oxidation of glycoproteins is based on theclassical Malaprade reaction described in 1928, the oxidation of vicinaldiols with periodate to form an active aldehyde group (Malaprade L.,Analytical application, Bull Soc Chim France, 1928, 43, 683-96).Additional examples for such an oxidizing agent are lead tetraacetate(Pb(OAc)₄), manganese acetate (MnO(Ac)₃), cobalt acetate (Co(OAc)₂),thallium acetate (TlOAc), cerium sulfate (Ce(SO₄)₂) (U.S. Pat. No.4,367,309) or potassium perruthenate (KRuO₄) (Marko et al., J Am ChemSoc 1997, 119, 12661-2) By “oxidizing agent” a mild oxidizing compoundwhich is capable of oxidizing vicinal diols in carbohydrates, therebygenerating active aldehyde groups under physiological reactionconditions is meant.

The second step is the coupling of the polymer containing an aminooxygroup to the oxidized carbohydrate moiety to form an oxime linkage. Inone embodiment of the invention, this step can be carried out in thepresence of catalytic amounts of the nucleophilic catalyst aniline oraniline derivatives (Dirksen A et Dawson P E, Bioconjugate Chem. 2008;Zeng Y et al., Nature Methods 2009; 6:207-9). The aniline catalysisdramatically accelerates the oxime ligation allowing the use of very lowconcentrations of the reagents. In another embodiment of the inventionthe oxime linkage is stabilized by reduction with NaCNBH3 to form analkoxyamine linkage (FIG. 2).

In one embodiment of the invention, the reaction steps to conjugate awater soluble polymer to a blood coagulation protein are carried outseparately and sequentially (i.e., starting materials (e.g., bloodcoagulation protein, water soluble polymer, etc), reagents (e.g.,oxidizing agents, aniline, etc) and reaction products (e.g., oxidizedcarbohydrate on a blood coagulation protein, activated aminooxy watersoluble polymer, etc) are separated between individual reaction steps).

Additional information on aminooxy technology can be found in thefollowing references, each of which is incorporated in their entireties:EP 1681303A1 (HASylated erythropoietin); WO 2005/014024 (conjugates of apolymer and a protein linked by an oxime linking group); WO96/40662(aminooxy-containing linker compounds and their application inconjugates); WO 2008/025856 (Modified proteins); Peri F et al.,Tetrahedron 1998, 54, 12269-78; Kubler-Kielb J et. Pozsgay V., J OrgChem 2005, 70, 6887-90; Lees A et al., Vaccine 2006, 24(6), 716-29; andHeredia K L et al., Macromoecules 2007, 40(14), 4772-9.

In various embodiments of the invention, the water soluble polymer whichis linked according to the aminooxy technology described herein to anoxidized carbohydrate moiety of a blood coagulation protein (e.g.,FVIII, FVIIa, or FIX) include, but are not limited to polyethyleneglycol (PEG), branched PEG, polysialic acid (PSA), carbohydrate,polysaccharides, pullulane, chitosan, hyaluronic acid, chondroitinsulfate, dermatan sulfate, starch, dextran, carboxymethyl-dextran,polyalkylene oxide (PAO), polyalkylene glycol (PAG), polypropyleneglycol (PPG) polyoxazoline, poly acryloylmorpholine, polyvinyl alcohol(PVA), polycarboxylate, polyvinylpyrrolidone, polyphosphazene,polyoxazoline, polyethylene-co-maleic acid anhydride,polystyrene-co-maleic acid anhydride, poly(1-hydroxymethylethylenehydroxymethylformal) (PHF),2-methacryloyloxy-2′-ethyltrimethylammoniumphosphate (MPC).

The following examples are not intended to be limiting but onlyexemplary of specific embodiments of the invention.

Examples Example 1 Preparation of the Homobifunctional LinkerNH₂[OCH₂CH₂]₂ONH₂

The homobifunctional linker NH₂[OCH₂CH₂]₂ONH₂

(3-oxa-pentane-1,5-dioxyamine) containing two active aminooxy groups wassynthesized according to Boturyn et al. (Tetrahedron 1997; 53:5485-92)in a two step organic reaction employing a modified Gabriel-Synthesis ofprimary amines (FIG. 3). In the first step, one molecule of2,2-chlorodiethylether was reacted with two molecules ofEndo-N-hydroxy-5-norbornene-2,3-dicarboximide in dimethylformamide(DMF). The desired homobifunctional product was prepared from theresulting intermediate by hydrazinolysis in ethanol.

Example 2 Preparation of the Homobifunctional Linker NH₂[OCH₂CH₂]₄ONH₂

The homobifunctional linker NH₂[OCH₂CH₂]₄ONH₂

(3,6,9-trioxa-undecane-1,11-dioxyamine) containing two active aminooxygroups was synthesized according to Boturyn et al. (Tetrahedron 1997;53:5485-92) in a two step organic reaction employing a modifiedGabriel-Synthesis of primary amines (FIG. 3). In the first step onemolecule of Bis-(2-(2-chlorethoxy)-ethyl)-ether was reacted with twomolecules of Endo-N-hydroxy-5-norbornene-2,3-dicarboximide in DMF. Thedesired homobifunctional product was prepared from the resultingintermediate by hydrazinolysis in ethanol.

Example 3 Preparation of Aminooxy-PSA

500 mg of oxidized PSA (MW=18.8 kD) obtained from the Serum Institute ofIndia (Pune, India) was dissolved in 8 ml 50 mM sodium acetate buffer,pH 5.5. Next, 100 mg 3-oxa-pentane-1,5-dioxyamine was added. Aftershaking for 2 hrs at room temperature, 44 mg sodium cyanoborohydride wasadded. After shaking for another 4 hrs at 4° C., the reaction mix wasloaded into a Slide-A-Lyzer (Pierce, Rockford, Ill.) dialysis cassette(3.5 kD membrane, regenerated cellulose) and dialyzed against PBS pH 7.2for 4 days. The product was frozen at −80° C. The preparation of theaminooxy-PSA according to this procedure is illustrated in FIG. 4.

Alternative Procedure for Preparation of Aminooxy PSA

1000 mg of oxidized PSA (MW=20 kD) obtained from the Serum Institute ofIndia (Pune, India) was dissolved in 16 ml 50 mM phospate buffer pH 6.0.Then 170 mg 3-oxa-pentane-1,5-dioxyamine was given to the reactionmixture. After shaking for 2 hrs at RT 78.5 mg sodium cyanoborohydridewas added and the reaction was performed for 18 hours over night. Thereaction mixture was then subjected to a ultrafiltration/diafiltrationprocedure (UF/DF) using a membrane with a 5 kD cut-off made ofregenerated cellulose (Millipore).

Example 4 Coupling of Aminooxy-PSA to rFIX and Purification of theConjugate

To 12.6 mg rFIX, dissolved in 6.3 ml 50 mM sodium acetate buffer, pH6.0, 2890 of an aqueous sodium periodate solution (10 mM) was added. Themixture was shaken in the dark for 1 h at 4° C. and quenched for 15 minat room temperature by the addition of 6.50 μl 1M glycerol. Lowmolecular weight contaminates were removed byultrafiltration/diafiltration (UF/DF) employing Vivaspin (Sartorius,Goettingen, Germany) concentrators (30 kD membrane, regeneratedcellulose). Next, 43 mg aminooxy-PSA was added to the UF/DF retentateand the mixture was shaken for 18 hrs at 4° C. The excess PSA reagentwas removed by hydrophobic interaction chromatography (HIC). Theconductivity of the cooled reaction mixture was raised to 180 mS/cm andloaded onto a 5 ml HiTrap Butyl FF (GE Healthcare, Fairfield, Conn.) HICcolumn (1.6×2.5 cm), pre-equilibrated with 50 mM HEPES, 3M sodiumchloride, 6.7 mM calcium chloride, 0.01% Tween 80, pH 6.9. The conjugatewas eluted within 2.4 column volumes (CV) with 50 mM HEPES, 6.7 mMcalcium chloride, 0.005% Tween 80, pH 7.4 at a flow rate of 5 ml/min.The preparation was analytically characterized by measuring totalprotein (BCA) and FIX chromogenic activity. For the PSA-rFIX conjugate aspecific activity of 80.2 IU/mg protein was determined (56.4% incomparison to native rFIX). The results are summarized in Table 1.

TABLE 1 Specific BCA FIX:Chrom Specific Activity Activity Item [mg/ml][IU/ml] [IU FIX:Chrom/mg BCA [%] rFIX 8.58 1221 142.3 100 PSA-rFIX 1.1592.2 80.2 56.4

The analytical characterization of the PSA-rFIX conjugate by SDS-PAGEwith Coomassie staining is illustrated in FIG. 5. An SDS-PAGE followedby Western blot employing anti-FIX and anti-PSA antibodies is shown inFIG. 6.

Example 5 Coupling of Aminooxy-PSA to rFIX in the Presence of Aniline asNucleophilic Catalyst

To 3.0 mg rFIX, dissolved in 1.4 ml 50 mM sodium acetate buffer, pH 6.0,14.10 of an aqueous sodium periodate solution (10 mM) was added. Themixture was shaken in the dark for 1 h at 4° C. and quenched for 15 minat room temperature by the addition of 1.50 μl 1M glycerol. Lowmolecular weight contaminates were removed by means of size exclusionchromatography (SEC) employing PD-10 desalting columns (GE Healthcare,Fairfield, Conn.). 1.2 mg oxidized rFIX, dissolved in 1.33 ml 50 mMsodium acetate buffer, pH 6.0 was mixed with 70 μl of aniline (200 mMaqueous stock solution) and shaken for 45 min at room temperature. Next,4.0 mg aminooxy-PSA was added and the mixture was shaken for 2 hrs atroom temperature and another 16 hrs at 4° C. Samples were drawn after 1h, after 2 hrs and at the end of the reaction after 18 hrs. Next, excessPSA reagent and free rFIX were removed by means of HIC. The conductivityof the cooled reaction mixture was raised to 180 mS/cm and loaded onto a5 ml HiTrap Butyl FF (GE Healthcare, Fairfield, Conn.) HIC column(1.6×2.5 cm), pre-equilibrated with 50 mM HEPES, 3M sodium chloride, 6.7mM calcium chloride, 0.01% Tween 80, pH 6.9. The conjugate was elutedwith a linear gradient to 50 mM HEPES, 6.7 mM calcium chloride, 0.005%Tween 80, pH 7.4 in 20 CV with at a flow rate of 5 ml/min.

Example 6 Coupling of Aminooxy-PSA to rFIX and Reduction with NaCNBH₃

To 10.5 mg rFIX, dissolved in 5.25 ml 50 mM sodium acetate buffer, pH6.0, 530 of an aqueous sodium periodate solution (10 mM) was added. Themixture was shaken in the dark for 1 h at 4° C. and quenched for 15 minat room temperature by the addition of 5.30 μl 1M glycerol. Lowmolecular weight contaminates were removed by means of UF/DF employingVivaspin (Sartorius, Goettingen, Germany) concentrators (30 kD membrane,regenerated cellulose). Next, 35.9 mg aminooxy-PSA was added to theUF/DF retentate and the mixture was shaken for 2 hrs at roomtemperature. Then 530 of a aqueous sodium cyanoborohydride solution (5M)was added and the reaction was allowed to proceed for another 16 hrs.Then the excess PSA reagent was removed by means of HIC. Theconductivity of the cooled reaction mixture was raised to 180 mS/cm andloaded onto a 5 ml HiTrap Butyl FF HIC (GE Healthcare, Fairfield, Conn.)column (1.6×2.5 cm), pre-equilibrated with 50 mM HEPES, 3M sodiumchloride, 6.7 mM calcium chloride, 0.01% Tween 80, pH 6.9. The conjugatewas eluted within 2.4 CV with 50 mM HEPES, 6.7 mM calcium chloride,0.005% Tween 80, pH 7.4 at a flow rate of 5 ml/min.

Example 7 Coupling of Aminooxy-PSA (Linker: NH₂[OCH₂CH₂]₄ONH₂) to rFIXand Purification of the Conjugate

To 5.6 mg rFIX, dissolved in 2.8 ml 50 mM sodium acetate buffer, pH 6.0,102 μl of an aqueous solution of sodium periodate (10 mM) was added. Themixture was shaken in the dark for 1 h at 4° C. and quenched for 15 minat room temperature by the addition of 2.9 μl of 1M glycerol. Lowmolecular weight contaminates were removed by means of UF/DF employingVivaspin (Sartorius, Goettingen, Germany) concentrators (30 kD membrane,regenerated cellulose). Then 19 mg aminooxy-PSA was added to the UF/DFretentate and the mixture was shaken for 18 hrs at 4° C. The excess PSAreagent was removed by means of HIC. The conductivity of the cooledreaction mixture was raised to 180 mS/cm and loaded onto a 5 ml HiTrapButyl FF (GE Healthcare, Fairfield, Conn.) HIC column (1.6×2.5 cm),pre-equilibrated with 50 mM HEPES, 3M sodium chloride, 6.7 mM calciumchloride, 0.01% Tween 80, pH 6.9. The conjugate was eluted within 2.4 CVwith 50 mM HEPES, 6.7 mM calcium chloride, 0.005% Tween 80, pH 7.4 at aflow rate of 5 ml/min.

Example 8 Coupling of Aminooxy-PSA to rFVIII

To 11 mg rFVIII, dissolved in 11 ml Hepes buffer pH 6 (50 mM Hepes, 5 mMCaCl₂, 150 mM NaCl, 0.01% Tween) 57 μl 10 mM sodium periodate was added.The mixture was shaken in the dark for 30 min at 4° C. and quenched for30 min at 4° C. by the addition of 107 μl of an aqueous 1M glycerolsolution. Then 19.8 mg aminooxy-PSA (18.8 kD) was added and the mixturewas shaken over night at 4° C. The ionic strength was increased byadding a buffer containing 8M ammonium acetate (8M ammonium acetate, 50mM Hepes, 5 mM CaCl₂, 350 mM NaCl, 0.01% Tween 80, pH 6.9) to get afinal concentration of 2.5M ammonium acetate. Next, the reaction mixturewas loaded on a HiTrap Butyl FF (GE Healthcare, Fairfield, Conn.) columnwhich was equilibrated with equilibration buffer (2.5M ammonium acetate,50 mM Hepes, 5 mM CaCl₂, 350 mM NaCl, 0.01% Tween 80, pH 6.9). Theproduct was eluted with elution buffer (50 mM Hepes, 5 mM CaCl₂, 0.01%Tween 80, pH 7.4), and the eluate was concentrated by centrifugalfiltration using Vivaspin (Sartorius, Goettingen, Germany) devices with30,000 MWCO.

Example 9 PK Studies in Hemophilic Mice

FIX-deficient mice were injected with either rFIX or PSA-rFIX (preparedaccording to Example 4) in formulation buffer (10 mM histidine, 260 mMglycine, 29 mM sucrose, 0.005% Tween 80, pH 6.8) in a volume dose of 10ml/kg bodyweight. Groups of 6 mice were sacrificed 5 minutes, 3 hours,9, 16, 24 and 48 hours after substance injection and blood was collectedby heart puncture. Citrated plasma was prepared and stored frozen untilanalysis of FIX activity.

FIX activity was determined with a chromogenic FIX assay (Biophen FIXassay, Hyphen Biomed, Neuville-sur-Oise, France) and elimination curveswere constructed (FIG. 7). Actual FIX activity doses were 123 IU FIX/kgfor PSA-rFIX and 143 IU FIX/kg for rFIX. Pharmacokinetic parameters werecalculated with program R (The R Foundation for Statistical Computing,2008). In vivo recovery was 13% for rFIX and 29% for PSA-rFIX. Doseadjusted AUC for PSA-rFIX increased 6.4-fold relative to rFIX, terminalhalf life increased by a factor of 1.2 and MRT was 1.7-times longer forPSA-rFIX compared to rFIX (Table 2).

TABLE 2 In vivo recovery AUC Increase Terminal Increase Increase Item[%] [(IU/ml)/(IU/kg)] factor HL [h] factor MRT [h] factor rFIX 13 0.0100=1 8.0 =1 7.3 =1 PSA-rFIX 29 0.0650 6.4x 9.6 1.2x 12.3 1.7x

Example 10 Polysialylation of Blood Coagulation Proteins

Polysialylation as described herein may be extended to other coagulationproteins. For example, in various aspects of the invention, the abovepolysialylation as described in Examples 5, 6 and 9 with aminooxy-PSA isrepeated with coagulation proteins such as FVIII, FVIIa and VWF.

Example 11 Preparation of the Homobifunctional Linker NH₂[OCH₂CH₂]₆ONH₂

The homobifunctional linker NH₂[OCH₂CH₂]₆ONH₂

(3,6,9,12,15-penatoxa-heptadecane-1,17-dioxyamine) containing two activeaminooxy groups was synthesized according to Boturyn et al. (Tetrahedron1997; 53:5485-92) in a two step organic reaction employing a modifiedGabriel-Synthesis of primary amines. In the first step one molecule ofhexaethylene glycol dichloride was reacted with two molecules ofEndo-N-hydroxy-5-norbornene-2,3-dicarboximide in DMF. The desiredhomobifunctional product was prepared from the resulting intermediate byhydrazinolysis in ethanol.

Example 12 Polysialylation of rFIX Employing a Maleimido/Aminooxy LinkerSystem

A. Preparation of the Modification Reagent

An Aminooxy-PSA reagent is prepared by use of a maleimido/aminooxylinker system (Toyokuni et al., Bioconjugate Chem 2003; 14, 1253-9).PSA-SH (20 kD) containing a free terminal SH-group is prepared using atwo step procedure: a) Preparation of PSA-NH₂ by reductive amination ofoxidized PSA with NH₄Cl according to WO05016973A1 and b) introduction ofa sulfhydryl group by reaction of the terminal primary amino group with2-iminothiolane (Traut's reagent/Pierce, Rockford, Ill.) as described inU.S. Pat. No. 7,645,860. PSA-SH is coupled to the maleimido-group of thelinker at pH 7.5 in PBS-buffer using a 10 fold molar excess of thelinker and a PSA-SH concentration of 50 mg/ml. The reaction mixture isincubated for 2 hours under gentle shaking at room temperature. Then theexcess linker reagent is removed and the aminooxy-PSA is bufferexchanged into oxidation buffer (50 mM sodium phosphate, pH 6.0) bydiafiltration. The buffer is exchanged 25 times employing a Pellicon XL5kD regenerated cellulose membrane (Millipore, Billerica, Mass.).

B. Modification of rFIX after Prior Oxidation with NaIO₄

rFIX is oxidized in 50 mM sodium phosphate buffer, pH 6.0 employing 100μM sodium periodate in the buffer. The mixture was shaken in the darkfor 1 h at 4° C. and quenched for 15 min at room temperature by theaddition of glycerol to a final concentration of 5 mM. Low molecularweight contaminates were removed by means of size exclusionchromatography (SEC) employing PD-10 desalting columns (GE Healthcare,Fairfield, Conn.). Oxidized rFIX is then spiked with aniline to obtain afinal concentration of 10 mM and mixed with the aminooxy-PSA reagent toachieve a 5 fold molar excess of PSA. The reaction mixture was incubatedfor 2 hours under gentle shaking in the dark at room temperature.

C. Purification of the Conjugates

The excess of PSA reagent and free rFIX is removed by means of HIC. Theconductivity of the reaction mixture is raised to 180 mS/cm and loadedonto a column filled with 48 ml Butyl-Sepharose FF (GE Healthcare,Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 3 M sodiumchloride, 6.7 mM calcium chloride, 0.01% Tween 80, pH 6.9. Subsequentlythe conjugate is eluted with a linear gradient of 60% elution buffer (50mM Hepes, 6.7 mM calcium chloride, pH 7.4) in 40 CV. Finally thePSA-rFIX containing fractions are collected and subjected to UF/DF byuse of a 30 kD membrane made of regenerated cellulose (Millipore). Thepreparation is analytically characterized by measuring total protein(BCA) and FIX chromogenic activity. For the PSA-rFIX conjugates preparedwith both variants a specific activity of >50% in comparison to nativerFIX is determined.

Example 13 Preparation of Aminooxy-PSA Reagent

An Aminooxy-PSA reagent was prepared according to Example 3. The finalproduct was diafiltrated against buffer, pH 7.2 (50 mM Hepes) using a 5kD membrane (regenerated cellulose, Millipore), frozen at −80° C. andlyophilized. After lyophilization the reagent was dissolved in theappropriate volume of water and used for preparation of PSA-proteinconjugates via carbohydrate modification.

Example 14 Pharmacokinetics of Polysialylated rFVIII in a FVIIIDeficient Knock Out Mouse Model

A PSA-FVIII conjugate was prepared according Example 8. The conjugateshowed a specific activity of 6237 IU/mg (FVIII activity determined bythe chromogenic assay; total protein determined by the Bradford assay)and had a polysialylation degree of 6.7 (mole PSA per mole FVIII) asmeasured by the Resorcinol assay (Svennerholm L, Biochim Biophys Acta1957; 24: 604-11).

FVIII deficient mice described in detail by Bi et al. (Nat Genet 1995;10:119-21) were used as a model of severe human hemophilia A. Groups of6 mice received a bolus injection (200 IU FVIII/kg) via the tail veinwith either PSA-rFVIII prepared according to Example 8 or native rFVIII(ADVATE, Baxter Healthcare Corporation) in a dose of 200 IU FVIII/kgbodyweight. Citrate plasma by heart puncture after anesthesia wasprepared from the respective groups 5 minutes, 3, 6, 9, 16, 24, 32 and42 hours after injection. FVIII activity levels were measured in plasmasamples by use of the chromogenic assay. The results of this experimentare summarized in Table 3 and illustrated in FIG. 8. All calculationswere performed with R version 2.10.1 (A language and environment forstatistical computing. R Foundation for Statistical Computing, Vienna,Austria. website: R-project.org.). As a result the mean residence time(MRT) increased from 5.4 h (Advate control) to 11.1 h for the PSA-rFVIIIconjugate.

TABLE 3 Mean In vivo AUC 0-24 Terminal residence Clearance recovery(IU/ml · h)/ half- time CL Item IVR % IU/kg life (h) MRT (h) (ml/h/kg)PSA- 71 0.161 7.2 11.1 6.0 rFVIII rFVIII 58 0.054 4.4 5.4 17.1 control(Advate)

Example 15 Detailed Synthesis of the Aminooxy-PSA Reagent

3-oxa-pentane-1,5 dioxyamine was synthesized according to Botyryn et al(Tetrahedron 1997; 53:5485-92) in a two step organic synthesis asoutlined in Example 1.

Step 1:

To a solution of Endo-N-hydroxy-5-norbonene-2,3-dicarboxiimide (59.0 g;1.00 eq) in 700 ml anhydrous N,N-dimetylformamide anhydrous K₂CO₃ (45.51g; 1.00 eq) and 2,2-dichlorodiethylether (15.84 ml; 0.41 eq) were added.The reaction mixture was stirred for 22 h at 50° C. The mixture wasevaporated to dryness under reduced pressure. The residue was suspendedin 2 L dichloromethane and extracted two times with saturated aqueousNaCl-solution (each 1 L). The Dichloromethane layer was dried overNa₂SO₄ and then evaporated to dryness under reduced pressure and driedin high vacuum to give 64.5 g of3-oxapentane-1,5-dioxy-endo-2′,3′-dicarboxydiimidenorbornene as awhite-yellow solid (intermediate 1).

Step 2:

To a solution of intermediate 1 (64.25 g; 1.00 eq) in 800 ml anhydrousEthanol, 31.0 ml Hydrazine hydrate (4.26 eq) were added. The reactionmixture was then refluxed for 2 hrs. The mixture was concentrated to thehalf of the starting volume by evaporating the solvent under reducedpressure. The occurring precipitate was filtered off. The remainingethanol layer was evaporated to dryness under reduced pressure. Theresidue containing the crude product 3-oxa-pentane-1,5-dioxyamine wasdried in vacuum to yield 46.3 g. The crude product was further purifiedby column chromatography (Silicagel 60; isocratic elution withDichloromethane/Methanol mixture, 9+1) to yield 11.7 g of the pure finalproduct 3-oxa-pentane-1,5-dioxyamine.

Example 16 Polysialylation of rFIX Using PSA Hydrazide

rFIX is polysialylated by use of a PSA hydrazide reagent, which wasprepared by reaction of oxidized PSA with adipic acid dihydrazide (ADH).

Step 1: Preparation of PSA Hydrazide

500 mg of oxidized PSA (MW=20 kD) obtained from the Serum Institute ofIndia (Pune, India) was dissolved in 8 ml 50 mM sodium acetate buffer,pH 5.5. 100 mg adipic acid dihydrazide (ADH) was then added. Thesolution was gently shaken for 2 hrs. 44 mg sodium cyanoborohydride werethen added. After the reaction was incubated for an additional 4 hrs at4° C., the reaction mix was loaded into a Slide-A-Lyzer (Pierce,Rockford, Ill.) dialysis cassette (3.5 kD membrane, regeneratedcellulose) and dialyzed against PBS pH 7.2 for 4 days. The product wasfrozen at −80° C.

Step 2: Reaction of PSA Hydrazide with rFIX and Purification of theConjugate

rFIX is polysialylated by use of a PSA hydrazide reagent as described inStep 1. rFIX (concentration 1 mg/ml) is oxidized withNaIO₄(concentration: 80 μM) for 1 h at 4° C. in the dark under gentleshaking. The reaction is stopped by addition of glycerol and theoxidized FIX is subjected to UF/DF by use of a 30 kD membrane made ofregenerated cellulose (Vivaspin). The oxidized rFIX is thenpolysialylated at pH 6.5 using a 200-fold molar excess of reagent and aprotein concentration of 1 mg/ml. rFIX and the polysialyation reagentare incubated for 2 hours under gentle shaking in the dark at roomtemperature. Finally, the PSA-rFIX conjugate is purified by HIC. Theconductivity of the reaction mixture is raised to 130 mS/cm by adding abuffer containing ammonium acetate (50 mM Hepes, 350 mM NaCl, 5 mMCalcium chloride, 8M ammonium acetate, 0.01% Tween 80, pH 6.9) andloaded onto a HiTrap Butyl FF column (5 ml, GE Healthcare, Fairfield,Conn.) pre-equilibrated with 50 mM Hepes, 2.5M ammonium acetate, 350 mMsodium chloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6.9.Subsequently, the conjugate is eluted with 50 mM Hepes, 5 mM calciumchloride, 0.01% Tween 80, pH 7.4. Finally the PSA-rFIX containingfractions are collected and subjected to UF/DF by use of a 30 kDmembrane made of regenerated cellulose (Vivaspin). For the PEG-rFIXconjugate, a specific activity of >50% in comparison to native rFIX isdetermined (chromogenic assay).

Example 17 Polysialylation of rFIX Using PSA Hydrazide in the Presenceof Aniline as a Nucleophilic Catalyst

123 mg rFIX are dissolved in 60 ml phosphate buffer (50 mM NaPO₄, pH6.5) buffer. Then 1.2 ml of an aqueous sodium periodate solution (10 mM)is added and the mixture is incubated for 1 h in the dark at 4° C. undergentle stirring. Subsequently the reaction is quenched for 15 min at RTby the addition of 600 μl of 1M aqueous glycerol solution. The mixtureis subsequently subjected to UF/DF employing a Pellicon XL Ultracel 30kD membrane.

The UF/D F retentate (63.4 ml), containing oxidized rFIX, is furtherdiluted with 59.6 ml phosphate buffer (50 mM NaPO₄, pH 6.0) and mixedwith 6.5 ml of an aqueous aniline solution (200 mM) and incubated for 30min at RT. Then 12.3 ml of the PSA-hydrazide reagent (prepared accordingExample 16) is added to give a 5 fold molar reagent excess. This mixtureis incubated for 2 h at RT in the dark under gentle stirring.

The excess of the PSA-hydrazide reagent and free rFIX is removed bymeans of HIC. The conductivity of the reaction mixture is raised to 180mS/cm and loaded onto a column filled with 48 ml Butyl-Sepharose FF (GEHealthcare, Fairfield, Conn.) pre-equilibrated with 50 mM Hepes, 3Msodium chloride, 6.7 mM calcium chloride, 0.01% Tween 80, pH 6.9.Subsequently the conjugate is eluted with 50 mM Hepes, 5 mM calciumchloride, 0.01% Tween 80, pH 7.4. Finally the PSA-rFIX containingfractions are collected and subjected to UF/DF by use of a 30 kDmembrane made of regenerated cellulose (Millipore). The preparation isanalytically characterized by measuring total protein (BCA) and FIXchromogenic activity. For the PSA-rFIX conjugate a specific activityof >50% in comparison to native rFIX is determined.

Example 18 Polysialylation of rFIX and Purification Using a Two StepProcedure

140 mg rFIX was dissolved in 62 ml phosphate buffer (50 mM NaPO₄, pH6.0) buffer. Then 1.92 ml of an aqueous sodium periodate solution (10mM) were added and the mixture was incubated for 1 h in the dark at 4°C. under gentle stirring and quenched for 15 min at RT by the additionof 640 of an 1M aqueous glycerol solution. Subsequently the mixture wassubjected to UF/DF employing a Pellicon XL Ultracel 30 kD membrane.

The UF/DF retentate (69.4 ml), containing oxidized rFIX, was furtherdiluted with 73.8 ml phosphate buffer (50 mM NaPO₄, pH 6.0), mixed with8.2 ml of an aqueous aniline solution (200 mM) and incubated for 30 minat RT. Then 12.3 ml of the aminooxy reagent (prepared according toExample 3) were added to give a 2.5 fold molar reagent excess. Thismixture was incubated for 2.5 h at RT in the dark under gentle stirring.

The free rFIX is removed by means of anion exchange chromatography(AIEC). The reaction mixture is diluted with 20 ml Buffer A (50 mMHepes, 5 mM CaCl₂, pH 7.5) and loaded onto a Q-Sepharose FF 26/10 column(GE Healthcare, Fairfield, Conn.) pre-equilibrated with Buffer A. Thenthe column is eluted with Buffer B (50 mM Hepes, 1M NaCl, 5 mM CaCl₂, pH7.5). Free rFIX elutes at a conductivity between 12-25 mS/cm and theconjugate between 27-45 mS/cm. The conductivity of the conjugatecontaining fractions are subsequently raised to 190 mS/cm by addition ofBuffer C (50 mM Hepes, 5M NaCl, 5 mM CaCl₂, pH 6.9) and loaded onto aButyl Sepharose FF 26/10 column (GE Healthcare, Fairfield, Conn.)pre-equilibrated with Buffer D (50 mM Hepes, 3M NaCl, 5 mM CaCl₂, pH6.9). Free PSA-reagent is washed out within 5 CV Buffer D. Subsequentlythe conjugate is eluted with 100% Buffer E (50 mM Hepes, 5 mM CaCl₂, pH7.4). The conjugate containing fractions are concentrated by UF/DF usinga 10 kD membrane made of regenerated cellulose (88 cm², cut-off 10kD/Millipore). The final diafiltration step is performed againsthistidine buffer, pH 7.2 containing 150 mM NaCl and 5 mM CaCl₂. Thepreparation is analytically characterized by measuring total protein(BCA) and FIX chromogenic activity. For the PSA-rFIX conjugate aspecific activity of >50% in comparison to native rFIX is determined.

Example 19 Coupling of Aminooxy-PSA to rFVIIa and Purification of theConjugate

A solution of 10 mg rFVIIa in 5 ml reaction buffer (50 mM Hepes, 150 mMsodium chloride, 5 mM calcium chloride, pH 6.0) is mixed with an aqueoussolution of NaIO₄ (final concentration: 100 μM) and incubated for 1 h at4° C. under gentle stirring in the dark and quenched by the addition ofan aqueous solution of cysteine (final concentration: 1 mM) for 15 min.The reaction mixture is subsequently subjected to UF/DF. To theretentate (10 ml) a 30 fold molar excess of Aminooxy reagent (preparedaccording to Example 1) is added. The coupling reaction is performed for2 hours at room temperature in the dark under gentle shaking. The excessof aminooxy reagent is removed by HIC. The conductivity of the reactionmixture is raised to 130 mS/cm by adding a buffer containing ammoniumacetate (50 mM Hepes, 350 mM NaCl, 5 mM Calcium chloride, 8 M ammoniumacetate, 0.01% Tween 80, pH 6.9) and loaded onto a HiTrap Butyl FFcolumn (5 ml, GE Healthcare, Fairfield, Conn.) pre-equilibrated with 50mM Hepes, 2.5 M ammonium acetate, 350 mM sodium chloride, 5 mM calciumchloride, 0.01% Tween 80, pH 6.9. Subsequently the conjugate is elutedwith 50 mM Hepes, 5 mM calcium chloride, 0.01% Tween 80, pH 7.4 by alinear gradient of 100% elution buffer in 20 CV. Finally the PSA-rFVIIacontaining fractions are collected and subjected to UF/DF by use of a 30kD membrane made of regenerated cellulose (Vivaspin). The preparation isanalytically characterized by measuring total protein (BCA) and FVIIachromogenic activity (Staclot assay, Diagnostica Stago, Asnières,France) and shows a specific activity of >20% compared to the rFVIIastarting material.

Example 20 Coupling of Aminooxy-PSA to rFVIIa in the Presence of Anilineas Nucleophilic Catalyst

To 3.0 mg rFVIIa, dissolved in 1.4 ml 50 mM sodium acetate buffer, pH6.0, 14.10 of an aqueous sodium periodate solution (10 mM) is added. Themixture is shaken in the dark for 1 h at 4° C. and quenched for 15 minat room temperature by the addition of 1.50 μl 1M glycerol. Lowmolecular weight contaminates are removed by means of size exclusionchromatography (SEC) employing PD-10 desalting columns (GE Healthcare,Fairfield, Conn.). 3 mg oxidized rFVIIa, dissolved in 3 ml 50 mM sodiumacetate buffer, pH 6.0 is mixed with aniline (a nucleophilic catalyst,final concentration: 10 mM) and shaken for 30 min at room temperature.Next, aminooxy-PSA is added to give a 5 fold molar excess and themixture is shaken for 2 hrs at room temperature. Subsequently the excessPSA reagent and free rFIX are removed by means of HIC. The conductivityof the cooled reaction mixture is raised to 180 mS/cm and loaded onto a5 ml HiTrap Butyl FF (GE Healthcare, Fairfield, Conn.) HIC column(1.6×2.5 cm), pre-equilibrated with 50 mM Hepes, 3M sodium chloride, 6.7mM calcium chloride, 0.01% Tween 80, pH 6.9. The conjugate is elutedwith a linear gradient to 50 mM HEPES, 6.7 mM calcium chloride, 0.005%Tween 80, pH 7.4 in 20 CV with at a flow rate of 5 ml/min.

Example 21 Preparation of an Aminooxy-PEG Reagent

A branched PEG-aldehyde (MW 40 kD) is used for coupling to thediaminooxy linker, which is prepared as described in Example 1. ThisPEG-aldehyde reagent is available from NOF (NOF Corp., Tokyo, Japan).500 mg of PEG-aldehyde is dissolved in 8 ml 50 mM sodium acetate buffer,pH 5.5. Then 100 mg 3-oxa-pentane-1,5-dioxyamine is added. After shakingfor 2 hrs at room temperature, 44 mg sodium cyanoborohydride is added.After shaking for another 4 hrs at 4° C., the reaction mix is loadedinto a Slide-A-Lyzer (Pierce, Rockford, Ill.) dialysis cassette (3.5 kDmembrane, regenerated cellulose) and dialyzed against PBS pH 7.2 for 4days. The product is frozen at −80° C.

Example 22 PEGylation of rFIX with an Aminooxy PEG-Reagent

rFIX is PEGylated by use of a linear 20 kD PEGylation reagent containingan aminooxy group. An example of this type of reagent is the Sunbright®CA series from NOF (NOF Corp., Tokyo, Japan). rFIX is oxidized at aprotein concentration of 2 mg/ml with NaIO₄ (final: concentration: 100μM) for 1 hour under gentle shaking in the dark at 4° C. in reactionbuffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH6.0) and quenched by the addition of an aqueous solution of glycerol(final concentration: 1 mM) for 15 min. The reaction mixture issubsequently subjected to UF/DF. To the retentate a 3 fold molar excessof Aminooxy reagent and aniline (a nucleophilic catalyst, finalconcentration: 10 mM) are added. The coupling reaction is performed for2 hours at room temperature in the dark under gentle shaking. Finallythe PEG-rFIX conjugate is purified by ion-exchange chromatography onQ-Sepharose FF. 1.5 mg protein/ml gel is loaded on the column preequilibrated with 50 mM Tris, pH 8.0. The conjugate is eluted with 50 mMTris and 1 M sodium chloride, pH 8.0 in 20 CV and is then subjected toUF/DF using a 30 kD membrane. The preparation is analyticallycharacterized by measuring total protein (BCA) and FIX chromogenicactivity. For the PEG-rFIX conjugate a specific activity of >75% incomparison to native rFIX is determined.

Example 23 PEGylation of rFVIII with an Aminooxy PEG-Reagent

rFVIII is PEGylated by use of a linear 20 kD PEGylation reagentcontaining an aminooxy group. An example of this type of reagent is theSunbright® CA series from NOF (NOF Corp., Tokyo, Japan). rFVIII isoxidized at a protein concentration of 1 mg/ml with NaIO₄ (final:concentration: 100 μM) for 1 hour under gentle shaking in the dark at 4°C. in reaction buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calciumchloride, pH 6.0) and quenched by the addition of an aqueous solution ofcysteine (final concentration: 1 mM) for 15 min. The reaction mixture issubsequently subjected to UF/DF. To the retentate a 20 fold molar excessof Aminooxy reagent and aniline (a nucleophilic catalyst, finalconcentration: 10 mM) are added. The coupling reaction is performed for2 hours at room temperature in the dark under gentle shaking. Finallythe PEG-rFVIII conjugate is purified by ion-exchange chromatography onQ-Sepharose FF. 1.5 mg protein/ml gel is loaded on the column preequilibrated with 50 mM Hepes buffer, pH 7.4 containing 5 mM CaCl₂. Theconjugate is eluted with 50 mM Hepes buffer containing 5 mM CaCl₂ and500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a 30kD membrane. The analytical characterization of the conjugate by FVIIIchromogenic assay and determination of total protein (BCA assay) shows aspecific activity of >60% compared to the rFVIII starting material.

Example 24 PEGylation of rFVIIa with an Aminooxy PEG-Reagent

rFVIIa is PEGylated by use of a linear 20 kD PEGylation reagentcontaining an aminooxy group. An example of this type of reagent is theSunbright® CA series from NOF (NOF Corp., Tokyo, Japan). rFVIIa isoxidized at a protein concentration of 2 mg/ml with NaIO₄ (final:concentration: 100 μM) for 1 hour under gentle shaking in the dark at 4°C. in reaction buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calciumchloride, pH 6.0) and quenched by the addition of an aqueous solution ofglycerol (final concentration: 1 mM) for 15 min. The reaction mixture issubsequently subjected to UF/DF. To the retentate a 5 fold molar excessof Aminooxy reagent and aniline (a nucleophilic catalyst, finalconcentration: 10 mM) are added. The coupling reaction is performed for2 hours at room temperature in the dark under gentle shaking. Finallythe PEG-rFVIIa conjugate is purified by ion-exchange chromatography onQ-Sepharose FF. 1.5 mg protein/ml gel is loaded on the column preequilibrated with 20 mM Hepes buffer containing 1 mM CaCl₂, pH 7.4. Theconjugate is eluted with 20 mM Hepes buffer containing 1 mM CaCl₂ and500 mM sodium chloride, pH 7.4 and is then subjected to UF/DF using a 30kD membrane. The analytical characterization of the conjugate bymeasuring FVIIa activity (Staclot assay, Diagnostica Stago, Asnières,France) and total protein (BCA assay) shows a specific activity of >25%compared to the rFVIIa starting material.

Example 25 PEGylation of rFIX with an PEG-Hydrazide Reagent

rFIX is PEGylated by use of a linear 20 kD PEGylation reagent containinga hydrazide group. An example of this type of reagent is the Sunbright®HZ series from NOF (NOF Corp., Tokyo, Japan). rFIX is oxidized at aprotein concentration of 2 mg/ml with NaIO₄ (final: concentration: 100μM) for 1 hour under gentle shaking in the dark at 4° C. in reactionbuffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calcium chloride, pH6.0) and quenched by the addition of an aqueous solution of glycerol(final concentration: 1 mM) for 15 min. The reaction mixture issubsequently subjected to UF/DF. To the retentate a 50 fold molar excessof Hydrazide reagent and aniline (a nucleophilic catalyst, finalconcentration: 10 mM) are added. The coupling reaction is performed for2 hours at room temperature in the dark under gentle shaking. Finallythe PEG-rFIX conjugate is purified by ion-exchange chromatography onQ-Sepharose FF. The reaction mixture is loaded onto the column (1.5 mgprotein/ml gel), which is preequilibrated with 50 mM Tris-buffer, pH8.0. The conjugate is eluted with 20 CV Tris-buffer, pH 8.0 (50 mM Tris,1 M NaCl) and is then subjected to UF/DF using a 30 kD membrane. Thepreparation is analytically characterized by measuring total protein(BCA) and FIX chromogenic activity. For the PEG-rFIX conjugate aspecific activity of >50% in comparison to native rFIX is determined(chromogenic assay).

Example 26 Polysialylation of rFVIII in the Presence of 2 mM Aniline

rFVIII is transferred into reaction buffer (50 mM Hepes, 350 mM sodiumchloride, 5 mM calcium chloride, 0.01% TWEEN® 80, pH 6), diluted to aprotein concentration of 1 mg/ml and oxidized with NaIO₄ (final:concentration: 100 μM) for 1 hour under gentle shaking in the dark at 4°C. in reaction buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calciumchloride, pH 6.0) and quenched by the addition of an aqueous solution ofcysteine (final concentration: 1 mM) for 15 mM. The reaction mixture issubsequently subjected to UF/DF. To the retentate a 20 fold molar excessof Aminooxy reagent and aniline (a nucleophilic catalyst, finalconcentration: 2 mM) are added. The coupling reaction is performed for 2hours at room temperature in the dark under gentle shaking. The excessof aminooxy reagent is removed by means of HIC. The conductivity of thereaction mixture is raised to 130 mS/cm by adding a buffer containingammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calciumchloride, 8 M ammonium acetate, 0.01% TWEEN® 80, pH 6.9) and loaded ontoa column filled with 53 ml Butyl-Sepharose FF (GE Healthcare, Fairfield,Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mMsodium chloride, 5 mM calcium chloride, 0.01% TWEEN® 80, pH 6.9.Subsequently the conjugate is eluted with 50 mM Hepes, 5 mM calciumchloride, 0.01% TWEEN® 80, pH 7.4 Finally the PSA-rFIX containingfractions are collected and subjected to UF/DF by use of a 30 kDmembrane made of regenerated cellulose (Millipore, Billerica, Mass.).The preparation is analytically characterized by measuring total protein(BCA) and FVIII chromogenic activity. For the PSA-rFVIII conjugate aspecific activity of 80% in comparison to native rFVIII is determined.

Example 27 Polysialylation of rFVIII in the Presence of 10 mM Aniline

rFVIII is transferred into reaction buffer (50 mM Hepes, 350 mM sodiumchloride, 5 mM calcium chloride, 0.01% Tween 80, pH 6), diluted to aprotein concentration of 1 mg/ml and oxidized with NaIO₄ (final:concentration: 100 μM) for 1 hour under gentle shaking in the dark at 4°C. in reaction buffer (50 mM Hepes, 150 mM sodium chloride, 5 mM calciumchloride, pH 6.0) and quenched by the addition of an aqueous solution ofcysteine (final concentration: 1 mM) for 15 mM. The reaction mixture issubsequently subjected to UF/DF. To the retentate a 20 fold molar excessof Aminooxy reagent and aniline (a nucleophilic catalyst, finalconcentration: 10 mM) are added. The coupling reaction is performed for2 hours at room temperature in the dark under gentle shaking. The excessof aminooxy reagent is removed by means of HIC. The conductivity of thereaction mixture is raised to 130 mS/cm by adding a buffer containingammonium acetate (50 mM Hepes, 350 mM sodium chloride, 5 mM calciumchloride, 8 M ammonium acetate, 0.01% TWEEN® 80, pH 6.9) and loaded ontoa column filled with 53 ml Butyl-Sepharose FF (GE Healthcare, Fairfield,Conn.) pre-equilibrated with 50 mM Hepes, 2.5 M ammonium acetate, 350 mMsodium chloride, 5 mM calcium chloride, 0.01% TWEEN® 80, pH 6.9.Subsequently the conjugate is eluted with 50 mM Hepes, 5 mM calciumchloride, 0.01% TWEEN® 80, pH 7.4. Finally the PSA-rFIX containingfractions are collected and subjected to UF/DF by use of a 30 kDmembrane made of regenerated cellulose (Millipore, Billerica, Mass.).The preparation is analytically characterized by measuring total protein(BCA) and FVIII chromogenic activity. For the PSA-rFVIII conjugate aspecific activity of 80% in comparison to native rFVIII is determined.

Example 28 PEGylation of a Blood Coagulation Protein Using Branched PEG

PEGylation of a blood coagulation proteins (such as FIX, FVIII and FVIIaas described in Examples 22-25) may be extended to a branched or linearPEGylation reagent as described in Example 21, which is made of analdehyde and a suitable linker containing an active aminooxy group.

The invention claimed is:
 1. A method of preparing a modified bloodcoagulation protein, comprising: contacting an activated water solublepolymer to an oxidized carbohydrate moiety of a blood coagulationprotein under conditions that allow conjugation; said blood coagulationprotein is selected from the group consisting of i) a blood coagulationprotein with Factor IX (FIX) biological activity; and ii) a bloodcoagulation protein with Factor VIII (FVIII) biological activity; saidactivated water soluble polymer comprises an active aminooxy linker anda water soluble polymer, wherein said water soluble polymer is selectedfrom the group consisting of polysialic acid (PSA), polysaccharides,pullulan, chitosan, hyaluronic acid, chondroitin sulfate, dermatansulfate, starch, polyoxazoline, polyacryloylmorpholine, andpolyphosphazene; and said carbohydrate moiety is oxidized by incubationwith a buffer comprising an oxidizing agent selected from the groupconsisting of sodium periodate (NaIO₄), lead tetraacetate (Pb(OAc)₄) andpotassium perruthenate (KRuO₄); wherein an oxime linkage is formedbetween the oxidized carbohydrate moiety and the active aminooxy linkeron the activated water soluble polymer.
 2. The method of claim 1,wherein the water soluble polymer is PSA.
 3. The method of claim 2,wherein the PSA is comprised of about 10-300 sialic acid units.
 4. Themethod of claim 1, wherein the blood coagulation protein has FIXbiological activity.
 5. The method of claim 1, wherein the bloodcoagulation protein has FVIII biological activity.
 6. The method ofclaim 1, wherein the oxidizing agent is sodium periodate (NaIO₄).
 7. Themethod of claim 1, wherein the oxidized carbohydrate moiety of the bloodcoagulation protein is located in the activation peptide of the bloodcoagulation protein.
 8. The method of claim 1, wherein the activatedwater soluble polymer is activated PSA, and said activated PSA isprepared by reacting an activated aminooxy linker with oxidized PSA;wherein the activated aminooxy linker is selected from the groupconsisting of: a) a 3-oxa-pentane-1,5-dioxyamine linker of the formula:

and b) a 3,6,9-trioxa-undecane-1,11-dioxyamine linker of the formula:

wherein the PSA is oxidized by incubation with an oxidizing agent toform a terminal aldehyde group at the non-reducing end of the PSA. 9.The method of claim 8, wherein the activated aminooxy linker is3-oxa-pentane-1,5-dioxyamine.
 10. The method of claim 8, wherein theoxidizing agent is NaIO₄.
 11. The method of claim 1, wherein thecontacting of the oxidized carbohydrate moiety with the activated watersoluble polymer occurs in a buffer comprising a nucleophilic catalystwhich is aniline.
 12. The method of claim 1, further comprising the stepof reducing an oxime linkage in the modified blood coagulation proteinby incubating the modified blood coagulation protein in a buffercomprising a reducing compound selected from the group consisting ofsodium cyanoborohydride (NaCNBH₃) and ascorbic acid (vitamin C).
 13. Themethod of claim 12, wherein the reducing compound is sodiumcyanoborohydride (NaCNBH₃).
 14. The method of claim 1, wherein saidmodified blood coagulation protein has a specific activity of at least50% relative to an unmodified blood coagulation protein.
 15. The methodof claim 1, wherein said modified blood coagulation protein has aspecific activity of at least 60% relative to an unmodified bloodcoagulation protein.
 16. The method of claim 1, wherein said modifiedblood coagulation protein has a specific activity of at least 70%relative to an unmodified blood coagulation protein.
 17. The method ofclaim 1, wherein the linker comprises 1-50 ethylene glycol units. 18.The method of claim 1, wherein the linker has 2 or 4 ethylene glycolunits.
 19. The method of claim 2, wherein the PSA is comprised of 5-500sialic acid units.
 20. The method of claim 2, wherein the PSA has amolecular weight from 2,000 Da to 45,000 Da.
 21. The method of claim 2,wherein the PSA has a molecular weight from 3,000 Da to 35,000 Da. 22.The method of claim 2, wherein the PSA has a molecular weight from 5,000Da to 25,000 Da.
 23. The method of claim 1, wherein the oxidizedcarbohydrate moiety of the blood coagulation protein is located in theactivation peptide of the blood coagulation protein.
 24. The method ofclaim 1, wherein the blood coagulation protein is a full-length bloodcoagulation protein.
 25. The method of claim 1, wherein the bloodcoagulation protein has FVIII biological activity and is a full-lengthFVIII.
 26. The method of claim 3, wherein the blood coagulation proteinhas FVIII biological activity, the linker comprises 1-50 ethylene glycolunits, wherein the oxidizing agent is sodium periodate (NaIO₄).
 27. Themethod of claim 3, wherein the blood coagulation protein has FVIIIbiological activity, the linker has 2 or 4 ethylene glycol units,wherein the oxidizing agent is sodium periodate (NaIO₄).
 28. The methodof claim 1, wherein the blood coagulation protein has FVIII biologicalactivity, the water soluble polymer is PSA having a molecular weightfrom 3,000 Da to 35,000 Da, wherein the linker comprises 1-50 ethyleneglycol units, wherein the oxidizing agent is sodium periodate (NaIO₄).29. The method of claim 1, wherein the blood coagulation protein hasFVIII biological activity, the water soluble polymer is PSA having amolecular weight from 3,000 Da to 35,000 Da, wherein the linker has 2 or4 ethylene glycol units, wherein the oxidizing agent is sodium periodate(NaIO₄).
 30. The method of claim 1, wherein the blood coagulationprotein has FVIII biological activity and is a full-length FVIII,wherein the water soluble polymer is PSA having a molecular weight from3,000 Da to 35,000 Da, wherein the linker comprises 1-50 ethylene glycolunits, wherein the oxidizing agent is sodium periodate (NaIO₄).
 31. Themethod of claim 1, wherein the blood coagulation protein has FVIIIbiological activity and is a full-length FVIII, wherein the watersoluble polymer is PSA having a molecular weight from 3,000 Da to 35,000Da, wherein the linker has 2 or 4 ethylene glycol units, wherein theoxidizing agent is sodium periodate (NaIO₄).
 32. The method of claim 3,wherein the blood coagulation protein has FIX biological activity, thelinker comprises 1-50 ethylene glycol units, wherein the oxidizing agentis sodium periodate (NaIO₄).
 33. The method of claim 3, wherein theblood coagulation protein has FIX biological activity, the linker has 2or 4 ethylene glycol units, wherein the oxidizing agent is sodiumperiodate (NaIO₄).
 34. The method of claim 1, wherein the bloodcoagulation protein has FIX biological activity, the water solublepolymer is PSA having a molecular weight from 3,000 Da to 35,000 Da,wherein the linker comprises 1-50 ethylene glycol units, wherein theoxidizing agent is sodium periodate (NaIO₄).
 35. The method of claim 1,wherein the blood coagulation protein has FIX biological activity, thewater soluble polymer is PSA having a molecular weight from 3,000 Da to35,000 Da, wherein the linker has 2 or 4 ethylene glycol units, whereinthe oxidizing agent is sodium periodate (NaIO₄).